Here's a quote from someone in the Haskell community that says it well https://twitter.com/mattoflambda/status/1275469470559907840

> You thought Yesod was Rails? Nope. Yesod is a highly modular library for developing web applications with a few opinions and some scaffolds.

> IHP is Rails - all the components are glued together in a way that makes modularity difficult.