You would have to show me.
TAS B is bad example considering how difficult it is to actually step.
Lets take a move like 236B which is -20 on block. NM's 3B is i23, if you step G confirm that 236B has whiffed, I doubt you punish it on time...maybe in practice...
It's all well and good in theory, but in actuality...when you step G you have to confirm the whiff, which adds time and slows down your punishment. While with step attack you don't have those extra frames so you could punish something like a BB with 3B...and considering the fact that you get so much from 3B, It's a risk you want to take(since NM is probably fighting from behind). Also the other problem with Step G is the fact that NM was always excessively blocking so taking SG damage in the process.