But Plessie only appeared as yes a ridable character like Yoshi, but his only use is to slide/swim from point A-B in 5(6th as cameo) levels. But of course he's ment for players to work together by syncing there actions. And of course many found this difficult when it's not that hard. Plus levels like the ones in W-★ & W-Bowser made him look useless. You could of swam yourself to the other side.