Dividing by both 6 and 8 (also 2, 3, 4, 9, 12, 16, 18, ...) is easy in a duodecimal system. In a sexagesimal system it’s additionally easy to divide by 5, 10, 15, etc.

I’m not sure what your point is. If you have a family of 7 or 11, you’re probably going to have a bad time using positional arithmetic regardless.

The point here is that decimal is noticeably less efficient and less regular than some alternatives.