But when is the average engineer going to need to deeply understand functional programming vs needing to deeply understand SQL? The latter governs how your data

But when is the average engineer going to need to deeply understand functional programming vs needing to deeply understand SQL? The latter governs how your data is stored and mutated at rest while the former, while an influential flavor of programming, is ultimately not the model that won out in the market (and for good reasons IMO). Most of the volume of useful work to be done in programming is about state manipulation, which is mostly relational database operations, which is mostly about set theory. I think every engineer should learn foundations that best equip them for the market long term, and prioritize their order of attack along those investments which will earn them outsized value. Data structures and algorithms, set theory and distributed systems equip an engineer extremely well for that. I have a very hard time believing deep investments in functional programming and type theory would differentially pay off better. Now, if one's goal is not to optimize for the market, then I think the answer is a lot more broad.