Indeed, there is nothing irrational (in an epistemic way) about having hyperbolic time preference. However, this means that a classical decision algorithm is not conducive to achieving long term goals.

One way around this problem is to use TDT, another way is to modify your preferences to be geometric.

A geometric time preference is a bit like a moral preference... it's a para-preference. Not something you want in the first place, but something you benefit from wanting when interacting with other agents (including your future self).