As seadart already said, rolling a sea kayak will feel different from rolling a WW boat. But it's still the same roll. Assuming the boats fit you properly (this includes outfitting), if you fail in one and succeed in the other, something in your technique is not up to snuff.
I've been rolling both a Jackson Side Kick and various sea kayaks for years now. Switching back and forth has never been a problem.
For pool rolls, the WW boat is my go-to boat. It fits completely inside my truck bed, it weighs half what my sea kayak does, it takes up very little room in the pool (a huge consideration unless you go to a full Olympic size pool), and it is easier to get in and out of the pool facility's doors.
An added bonus is that you can actually *paddle* the little boat in the pool, unlike with a sea kayak. If you want to practice strokes or turns there, the WW boat's small size allows that.
Another bonus is that you do not worry about either spearing someone or having your boat damaged from spearing by someone else, in such a low-speed environment.
If you paddle the WW boat outdoors, it will also help you clean up stroke technique, because its inherent turniness is less tolerant of asymmetries in stroke.
If the price is good and the boat fits, I say go for it.
Kayak Motor Kit
PFD's (Life Jackets)
Canoe / Kayak Anchors
Canoe Pack Liner
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