It's all about minimizing cognitive overhead. This happens in a few ways when you use strict functional patterns and a tight domain model: - You can safely mak

It's all about minimizing cognitive overhead. This happens in a few ways when you use strict functional patterns and a tight domain model: - You can safely make more assumptions about how your program works - You can rely on your type checker like a to-do list when extending your program These two benefits require more discipline, but they make extension and support brain-dead easy. For the record, you don't need Haskell to enjoy these benefits, you can get them in Python or TypeScript too, as long as you're disciplined in how you design your system.