My Dad has a kyack that’s about 15’ long and sits two inside and he uses it on lakes mostly, but you could take it anywhere I suppose. The skirt keeps most/all the water out, but also gets your lower body heated up as it traps in the heat, if you’re paddling for some time. Although if conditions are calm, you can paddle without the skirt.
I’ve been on the little short ones for white water, and it sure is fun. Depends on what conditions are around you and where you’re going to use it.