Ah I see what you mean, but in this case they could've gone back and added -P as an alias for -p in ssh for instance. Similarly, it makes sense to make the brackets mandatory for scp to distinguish the path from the address, but then why not make ssh also support this format optionally?

Anyway, it's pure bikeshedding at this point, it's just that it's such a common annoyance for me that I can't help but nitpick.