Yeah, I dunno. I see your point and will certainly explore it, but I easily use tabs for both. I mostly use marks to skip around in a file and tabs for opening different files. Why? Because I can see them. The drawback with buffers (and too many marks and registers etc.) is that it's easy to lose track of where things are. So tabs make buffers easy- you can glance up and see where the file that you need is.

The numbering system is a little screwy (starting at 1 instead of 0) though.