Not sure where you're going with Cubchoo, or why you suddenly decided to mention that other ice-types are all winter-only gives him merit when Cubchoo itself doesn't exist out of Winter (and no hidden grottos don't count). Lapras can also be found outside of Winter iirc (and exists before Drayden).
It does help that it's the earliest (although as far as gyms go only Skyla is relevant), and the Ice Punch tutor exists for a great reliable move to use. Beartic's pretty bro for getting Superpower, but the main issue is that he doesn't get anything better than Icicle Crash for physical STAB, which is kind of lame, really. Not just that too, but his E4's performance pretty bad imo, no thanks to his wonderful speed (if he was faster he'd be a lot more useful against say Grimsley where he can just superpower everything to death). At least some use against Iris is cool (can Blizzard/IC hydreigon/haxorus, superpower aggron/lapras)