I thought he learned level up Earthquake in gen II, guess I was wrong. It's been too long since I played it lol. Even so, Piloswine did miracles for me in Crystal when I had it, I like experimenting with Pokemon on teams and he did a well above good job. I know in HG/SS him and Mamoswine are tanks, fierce physical attack.
Then how about this: Piloswine has 2 things to go for. Earthquake and an Ice move. Any good team should have those 2 on their team already, since every water type not named Magikarp learns Ice beam/Blizzard/Ice Punch anyway. And Piloswine doesn't even get Earthquake by leveling, thus you would need to waste the TM on him, while there are PLENTY other Pokemon that want Earthquake very much.
Ampharos isn't obtainable in Crstal though. And Piloswine is not that good, only use it if you don't have any other ice move on your team. It's still decent though
I completely forgot about Mareep, it's been so long since I played Crystal. As for Piloswine, if used right and with the right team he's a boss. Give him the right moves there ain't no stopping it in the game. With Lapras he's not that useful but with other water types he's a don.