I'm not sure I understand, is there some special casing going on with "(== 10)"? As I'm admittedly not aware of it.
Not anything major. It's just syntactic sugar for "\x -> x == 10".
How is it syntactic sugar? It's just applying "10" to the first parameter of "==".
Without parentheses, == is infix. (== 10) is an "operator section", and applies 10 to the second parameter of ==. (10 ==) would be the first parameter.