Sane defaults for most (all?) aspects of the run-of-the-mill CRUD app, a.k.a. "convention over configuration". Helps focus development energy on solving the problem at hand as opposed to on bike shedding or being slowed down due to decision fatigue.

AFAICT, one has to go with the conventions as far as possible. Straying off the beaten path can lead one to lose time fighting the framework.