I think LINQ is a special case of a monad comprehension. Syntax checked, type checked, composeable query languages (of which the "Structured" Query Language is only one example) are good things.

So far everywhere where I might have been tempted to use a Maybe monad comprehension, applicative functors were more clear anyhow.

Probably the Maybe monad most often, in usual code.

Or really as a shorter way of writing any smaller monadic code blocks.

I really look forward to using this new feature.

I don't know for sure until I try, but I think can be useful for logic monads.