It's funny, I remember looking at Quorum's anonymity layer Constellation and thinking to myself how odd it was they wrote it in Haskell; generally a sign there are no adults in the room when coming from a JPMC tier company where actual money will be piped through it. It turned out they had to rewrite it in Java to get it to function reliably.

I have no opinion on Cardano,but obviously something from the ML family is useful if you want to build smart contracts.