Fun thread - agree with Thomas and others that having a thicker rim and/or base can allow for a nice feel in the hand and can also be a nice addition for the creator because unlocking the inner from the outer curves gives a second design choice. Also it can allow you to use the plane of the rim as a design element - sometimes it is so nice you want to keep more of it around.
The flow of the curves overlaps with actual thickness of the work in our or a buyer's perception. We all know you can make a paper thin piece that still has a "clunkiness" to it - harder but possible to make a thicker piece that feels airy.