There is _something_ that one can discover when they try psychedelics. It is a non-normal experience and so by definition will have novel data. Is it useful though? So many people couldn't have been flatly wrong (but they said that about religion) - so there could be something to it. One of that is the realization that our sensory inputs, how we process them, and also how we understand ourselves, the world, and the separateness of the self from everything around us - are not preordained. The way we look at all of them is not the only way. We think the way we think because we've evolved to it. What we see is not the objective reality; it is just a filter through which we perceive it. This experience can allow someone who's prepared for it, to break out of their own patterned ways of thinking.

But - there is a reason we've evolved to perceive reality in this way. It allows us to survive. Material concerns - health, wealth, status etc. and extractive consumption which messes up "nature", and having ego/identity distinct from nature -- all of this serve useful, vital purposes. A person who's constantly tripping will find it difficult to survive both in modern and ancient times long enough to propagate their genes.

People search for profundity in these experiences, and sure there are some. But to really understand the world and nature, I think the lens of science - observation, empiricism, and the scientific process is a better bet. There unfortunately really isn't anything _deeper_ about life. And whatever there is, personal introspection aided by psychedelics cannot hold a candle against organized human scientific endeavor.

Also, messing with one's brain is dangerous. It is one of the least understood human organs, irreplaceable, and fundamental to life like few other things.