True, but not a huge real world issue in nearly all the relevant cases.
I can very easily have a fallible, asynchronous, multi-value, stateful, database connected computation that returns a Bool and use it in let’s say ‘filterM’.
Most transformers are already written for me.
Edit: switching between no effect and some effect is the tricky part though.
I find in practice that even though I don't have to write the transformers myself, `lift`ing and `unlift`ing things is a pain in the ass. Once you try a proper algebraic effect system, it's hard to feel like transformers are an adequate solution.
