[hopia]

My experience is that the most basic tasks have a very mature library base in my context (web domain). Such as typed web endpoints, web servers and clients, JSON parsing and working with databases. I expect some domains are even far more mature with Haskell.

However, when you explore more specific things like shipping emails via a 3rd party service, various authentication protocols, monitoring via external services, spinning up persistent job queues etc. you start running into odd problems that you need to debug and even possibly fix at library level. That may considerably slow down development.