It looks like the tires you have on there are pretty low rolling resistance. They look really good too. I'd stick with the white walls. What kind of benefit are you looking for? Dirt traction, road traction, smooth ride , rolling efficiency, style?
Slicks are perfect if your only doing street riding, Those tires would be perfect for highway riding or street riding, But if it were to rain Or a little gravel slipped under your tire. You'd go down very fast. I'd stick to the regular beach cruiser tires. Because even though they don't have knobbies on them. There still somewhat good in the rain. slicks will definitly remove vibration and mak ea smoother ride. So it's Apples and Oranges. It all depends where your riding.
Good luck! If you do get those slicks. remember to slow down more in corners.
They use slicks in GP motorcycle racing, drag racing, Indy, & F-1 because treads don't give traction... Rubber on the road is what gives traction!
Tread patterns are mainly to channel out the water from under the tire while rolling, & they don't help much if you hit a little gravel or sand.
If you run slicks? slow down if they get wet!!!
I actually like the tires that are close to looking like slicks, but still have a little tread on them.