Did you read what he said? There’s a plethora of water types. That means if you really want a fire type, you’ll have to deal with a plethora of Water types. Also, I play through Hoenn with Swampert, and every single play through I do, Swampert ends up overleveled, even when I don’t try to train it. It’s just really great in these games. The extra ground typing sets it apart from other water types, as instead of getting beaten up by Wattson and other electric trainers, it destroys them. Also, as mentioned, it is amazing on offense, and it also can serve as an HM Slave (of course, you’d give it the strong HMs, like Surf, Waterfall, Dive, Strength, etc. since it’s strong). There are few to no instances where you should use a Fire type that Swampert couldn’t do as well anyways.