Whenever I hear or read someone who has adopted an 'Eastern'-type of religion or spirituality (modelled on Zen/ Buddhism, Hinduism or the like); I feel the horror of a viewpoint that this life, this world, is illusion - temporary, insignificant in itself.
The suffering of life is hear dealt-with by denying its significance. This deals with the suffering - but at the cost of making (or trying to make) the whole business futile.
If that was the whole story, the obvious conclusion would be to get-out-of life as quickly as possible: suicide - and it is noteworthy that in the real-life Eastern religions suicide is harshly penalised (with adverse consequences beyond death) - except in specific and socially-controlled situations (such as the 'honour' of seppuku).
But in The West, lacking such social sanctions, Eastern-style religiosity is a life-draining doctrine. It saves from the horror of life, but at the lethal cost of destroying real significance in anything that could possibly happen in life. All is illusion - good, bad and indifferent alike are illusion - and all is soon washed away...
Another factor is the individual's ultimate yearning; and this may be a key. It seems to me that there are those in the world for whom the highest good they can imagine is a state of permanent bliss - with only enough self-awareness to be aware of that bliss.
For such people, the business of mortal life, in a mortal world; the business of loving 'personal relationships' in a marriage, a family, a deep friendship; the business of creativity... all such businesses fail to interest, satisfy, inspire...
For such people; even if they were 100 percent sure of the creation of God the Father and the reality of the promises of Jesus Christ; 100% sure of the reality of the Christian Heaven and of living in a personal and loving relationship with God the Father and Jesus Christ; even if (for Mormon Christians) they were sure of eternal celestial marriage, of living and growing and developing towards divinity in eternal families...
Even if all this was known to be true and as represented - the problem would remain that such people do not like or want such things. They do not want love, creativity, or 'other people'... They simply want eternal impersonal unaware bliss.
For such people, mortal life really is understood to be a waste of time and effort - the sufferings cannot possibly be compensated by anything good that might happen - they want out of life; and the only thing that stops them is fear that this will make matters even worse.
As I am a Christian who values (some) other people, love, and creation - these things do matter more than anything to me; but I can understand the perspective from which they do not - and that some people really want nothing more from reality than a pleasing state of permanent-opt-out. And I presume that Heavenly Father has made provision for this desire - perhaps many such spirits have been incarnated into Eastern countries for such reasons...
However, a perhaps-surprising number of self-identified Christians have a perspective on this-world which is not much different from the Eastern view described above - with an almost-wholly negative view of life, and an aspiration for the after-life which is hardly-distinguishable from that 'static' state of Nirvana I described above.
This is perhaps mainly due to the 'Platonic' metaphysical framework of many mainstream Christians (strong since the very early years of Christianity, imported from pre-Christian Roman paganism) that sees post-mortal life in Heaven as perfection, permanence and reality; in contrast to earthly mortal life which is ultimately corrupt and changing and therefore unreal. Platonic Christianity may therefore become, in practice, very similar to Eastern religions - especially in its monastic and contemplative forms (which tend to be the most highly valued in this type of Christianity).
My understanding is that Christians need a metaphysics which values this world, which values it positively - and not merely in terms of avoiding damnation, and which regards at least some aspects of our mortal life as of permanent significance; indeed of permanent reality.
And these aspects are exactly what potentially gives absolute, positive and eternal value to mortal life.
And the fact that our bodies will die and the earth itself is impermanent does not affect that fact.
If Heaven is seen in terms of being like these most significant experiences aspects of mortal life - then the experiences of Christian Heaven are to-do-with Love as an eternally creative, growing, developing and unfolding relationship between persons. This is the essence of creation - creation is personal.
(Persons including fully-divine persons as well as Men - and the rest of the world is seen as alive and conscious and relate-able: in Heaven there are no 'things'.)
For me; the experiences that affect me most deeply in mortal life are seen by me as those which I consciously know to be real and permanently valuable. This value is not a matter of memory, it is not washed away by time or age or death - it is eternal.
(How this 'works' I am not sure; but that it works I am sure.)
To answer the question 'Does nothing really matter?' The answer is that some of our life experiences do really matter - indeed, in an eternal perspective, nothing matters more than these experiences.