Money and the possessions, security, and fulfillment that money can provide are not Biblically sinful. They are not the same as arrogance or greed or a focus on material prosperity over philosophical truths and how one treats others. A person could err by having these intentions without having money or a vast range of possessions, and having money or what it can purchase does not necessarily have these priorities or motivations. It remains irrational to think that the security or pleasure offered by money cannot wane or vanish altogether. Whether due to social disorder or personal negligence or some other metaphysical possibility such as object permanence ceasing to be part of our perceptions, there are scores of ways that money and possessions could fail to endure. This is part of what Jesus addresses in Matthew 6:19-21, but this alone would be incomplete and actually have dire ramifications for the standing of humanity.
These verses are where Jesus famously reminds his audience that "moths and rust" can destroy the material items people find pleasure or even, for some, an illusory kind of grand existential comfort in. Nowhere here does Jesus say that wealth and possessions are evil. Moreover, there are multiple Biblical examples that would contradict him if he had said such a thing. Job was directly blessed by God with abundant animals and other wealth (Job 1); material prosperity of everything from agricultural growth and beyond was one of the promised conditions if only the Israelites would consistently submit to Mosaic Law (Deuteronomy 28). Ultimately, that the Bible nowhere condemns having or wanting wealth means that it is not morally problematic just to have it or hope for it (Deuteronomy 4:2). What Jesus is drawing attention to is the futility of pursuing what in some contexts amounts to consumerism, as Americans might call it.
This much that Jesus says is true. It is of course possible for even the most pristine or durable belonging to be reduced to decay, to in some way lose its initial status of wholeness or to be taken away by some circumstance. Possessions of all kinds can be lost, stolen, damaged, or completely destroyed, and a life of blind or consumeristic indulgence neither prepares someone to experientially grapple with these facts nor amounts to anything more than an embrace of the sheer stupidity of emotionalistic irrationalism. However, there is a fallacious conclusion some people come to in their non sequitur-based worldview. Some might believe or say that humans matter more than products and other possessions because the latter can deteriorate, and this is a contradictory ideology and thus is logically incapable of being true, for people are also subject to decay.
People, too, can be harmed or weakened to the point of death, so it is not as if it is possible only for material possessions to lose their condition or even their very existence. It also does not logically follow from something ceasing to exist or it being possible for it to cease to exist that it lacks value. Of course, nothing is valuable because someone wishes it is or because their emotional perceptions would make it seem that way; all value is objectively tied to the nature of something (though there can be no anchor for this without an uncaused cause with a moral nature) or there is objectively no such thing as value, only things that are true or that exist amorally. It is not that people are more valuable than possessions because possessions can expire, for the very same thing is true of humans. Lasting forever is not a philosophical necessity for something to be objectively valuable, but, in Christian theology, immortality is nonetheless offered to all so that they can escape annihilation in hell (Ezekiel 18:4, Mathew 10:28).
The difference is that people are conscious beings capable of grasping the laws of logic (they, like everything else, already by necessity depend on them anyway), aligning themselves with any moral obligations that exist, and honoring the uncaused cause that directly or indirectly set human life in motion. No, even if the Christian worldview is true, it is not the case that anything that does not last forever or last forever by default is meaningless, for not only can humans become injured or die in this life, but the very second death suffered in hell is just that: a death of the soul, its removal from existence. The first and second deaths are integral in Christian doctrine and yet one of its central tenets is that all people have intrinsic, great value because they bear God's image--yet even animals have value and thus moral rights on the Biblical worldview (Mosaic Law emphasizes this repeatedly), and they are not even said to receive some special offer of eternal life or comprehend the same philosophical truths all people can if only they try! Moth and rust can eat away at inanimate objects, but so much more can eat away at the bodies of human beings, and this is not what dictates whether humans are or are not valuable.