The differences are problematic.

For example:

There is no visual options to invert the nav-menus or the showcase in T3_blank.

And even if I enable the Off Canvas option in T3_Blank I never see the module appear in the layout.

And where is the showcase?

Perhaps I am missing something here but I would really like the explanation.

These things cause T3 to be very confusing and difficult to use.

Thanks,
Bill S.