Afterburner has physical projectile as well. But the window looks so small that I wouldnt rely on it at all for that purpose.
To slightly remedy this some players go into Lv 1 with Afterburner. Then Lv 2. As opposed to trying to go to Lv 2 in one go, getting hit, and getting no Lv in. So if there hit during their attempt to go into Lv 2, their still guaranteed at least Lv 1 Heat Up. I doing two back to back is a bit faster then doing one long one, at least it looks like that visually.
I look at the Heat Levels pretty differently. Maybe it's because Im used to managing charges/levels because of playing Tsubaki. But I'd rather get 2 small confirms and then into a heavy damaging one with Lv 2 as opposed to just continuous mediocre confirms with Lv 1.