Step back and take an honest look, and in the vast majority of systems, it's hard to deny that stored functions and/or procedures are one of the most powerful tools in the toolbox. If anything, they're widely underutilized. This is especially the case with Postgres -- it has built-in support for functions in several non-SQL languages (including Python).

In practice, the aversion to stored funcs/procs mostly arises from political concerns. Most devs don't understand databases very well, and in most companies, independent DBA teams and independent dev teams end up burning tons of energy fighting for turf.

One of the advantages of a startup is that the smart people are free to utilize the best tools in the toolbox for the problem at hand, rather than having to conform to the social mores around "don't use that tool because it's under the control of the other team and we'll never be allowed to touch it again".