Functional languages are harder to understand than normal imperative ones, so it may take you a while to figure out.
Understanding how to use functional languages, however, is a really good thing to know if you want to do graduate work. The syntax/style is much closer to formal discrete mathematics used in computer science, so a lot of what you read in research papers will be almost directly portable to a functional program.
Outside of graduate studies and research though... they're not used so much.
Regardless, I think that's a really smart decision on their part to switch to Haskell from Python. Even though you may not use functional languages in work really, it will make you a better programmer in any paradigm. This is because in functional programming, if your program isn't pretty much
exactly correct - it simply won't do anything. Imperative programs tend to let you get away with a lot of things
.