The problem with Aero players is that they're too damn predictable, which allows scenarios like this to happen so often. Lead's alive and at 100%, you have rocks up, they don't. That puts you at a disadvantage.
Now imagine I see the other suicide lead and I, dunno, attacked instead. You wasted a turn trying to kill me when you know you couldn't, and didn't go for the SR right away because you were expecting the Taunt. Now your lead is dead, no rocks up, you still have a 130 base Speed attacker on your hands. If your best check to that is something slow and bulky, I'm getting Rocks up anyway. If it's Flygon, I switch to a Flygon counter and bring Aero in when he's safe. Either way, your lead is gone, mine is alive, and I still have a chance to get rocks up.
Aerodactyl doesn't just use Taunt, SR, then die, he dominates the lead game to the point where his worst match-up is himself. If you play him correctly, he'll both SR and leave a nice hole in your team before he goes.