They have exactly the same "power," they're just spelled differently. "func()" doesn't let you do anything that you can't do with "callable.call()". It's trivia

They have exactly the same "power," they're just spelled differently. "func()" doesn't let you do anything that you can't do with "callable.call()". It's trivial to do everything that isn't syntactic sugar (for example, partial application, passing as arguments for abstraction) that you mention in Java, if a bit tedious (and often pointless, since the standard APIs generally weren't designed with that in mind.) _A Little Java, A Few Patterns_ came out in 1998; give it a read.