not speaking in any official capacity, but: we great internal training material courtesy of some very thoughtful folks, and ultimately one hopes that most of the code is going to be pretty straightforward wherever possible.

There are two countervailing effects when you choose a more theoretically advanced programming language. On the one hand, your hiring pool shrinks. On the other hand, the quality of the remaining hiring pool goes way up, which acts as an excellent recruiting filter (for both employer and employee). Jane Street made a similar play with OCaml.