Some people believe in rebirth after this life because (for them) it seems that the suttas claim literal rebirth.
And it somewhat makes sense because in some passages it'd be harder to believe in "just" mental birth, especially here:
"With the break-up of the body, re-appeared in..." (difficult here ro believe that body means the "body" of the 5 aggregates)
"Now this, bhikkhus, is the noble truth of suffering: birth is suffering, aging is suffering, illness is suffering, death is suffering; union with what is displeasing is suffering; separation from what is pleasing is suffering; not to get what one wants is suffering; in brief, the five aggregates subject to clinging are suffering. “Now this, bhikkhus, is the noble truth of the origin of suffering: it is this craving which leads to renewed existence, accompanied by delight and lust, seeking delight here and there; that is, craving for sensual pleasures, craving for existence, craving for extermination.
Elsewhere I read that birth (jati) means birth in a particular realm (mind dwelling), which is caused by a sense of "I", and this in turn is caused by craving & the underlying asavas, but even if this is true (& per the sutta it arguably is), Why have samvega (sense of urgency that death may strike) without believe in literal rebirth
Why not live a normal life? This may sound provocative, but it really should not. Surely one can reply "because suffering", but most people living their live imperfectly okay, with some suffering here & there, but still find meaning & go through live with all its ups & downs.
With warm wishes.