You can still use your secondary basic attacks, spells, buffs, skills. The time spent between skills is almost negligible, 7 seconds at the most if you're waiting for a large TP consumption skill like Victimize. Let's take Pugilist for example, you could throw in Pummel, Flurry or Light Strike in there. Re-cast any buffs like Featherfoot or even Blindside if you were going to use Pounce. If you're tanking it gives you time to use your taunts again. All of this is simply more convenient with auto-attack simply because you do not have to return to Row 1 Space 1 to throw that regular attack in there every time.