[tikhonj]

The practical upside is that it makes using higher-order functions much smoother, with less distracting visual noise.

In Haskell this comes up all over the place. It's somewhat nice for "basic" cases (`map (encode UTF8) lines` vs `map (\ line -> encode UTF8 line) lines`) and, especially, for more involved examples with operators: `encode <$> readEncoding env <*> readStdin` vs, well, I don't even know what...)

You could replace the latter uses with some alternative or special syntax that covered the most common cases, like replacing monads with an effect system that used direct syntax, but that would be a lot less flexible and extensible. Libraries would not be able to define their own higher-order operations that did not fit into the effect system without incurring a lot of syntactic overhead, which would make higher-order abstractions and embedded DSLs much harder to use. The only way I can think of for recovering a similar level of expressiveness would be to have a good macro system. That might actually be a better alternative, but it has its own costs and downsides!