My guess would be yes, ridges do provide a little friction hence more agitating to aide in making the lather. I compare it to whiskers...When I face lather the first pass, the lather seems to peak up quicker and thicker than my second pass, after my face is already fairly smooth. The whiskers seem to help agitate the soap providing a superior lather. That's just my .02 cents...
i'll let you know my thoughts once my dirtybird arrives - I CAN get a decent lather in a smooth bowl, but assume the ridges will cut the time substantially
A lot of guys here prefer the ridges, but one of the scuttle manufactures claims they make no difference. That doesn't stop her from offering them, though.
I have never used a lathering bowl, let alone a scuttle, with a patterned interior and have never had a problem generating lather in a smooth bowl. I'd like to try a one sometime.
I also prefer ridges to a smooth surface, or at least a non-smooth texture.
On the other hand I have no problem getting a good lather from a smooth bowl either.