Generate .SM from playing over song?

This seems like a completely obvious feature so I'll be surprised if no one's mentioned it before. Alas I cannot find it so I am posting here.

Is it possible to create an SM file by actually pushing the arrow (or numbers 1-4) keys WHILE a song is playing in the editor? Wouldn't it be so much easier to just play the song in some sort of "record mode" where whatever notes you pushed while the song audio plays it would write that out as an SM file?

It's known as Record Mode, and you turn it on by selecting a region and hitting Ctrl+R.
Steps will be snapped to the current quantization. So if you're currently placing 16ths, then in Record Mode, your presses will be snapped to the nearest 16th.
Every skilled step artist I know considers it the worst way to make a chart, because it typically leads to incorrect rhythms and poorly considered step placement.

And it's not as accurate as you think it is by the way with going to the nearest quantization after you hit the key.

Next to no one uses this feature seriously due to how much editting stepcharts usually take anyways.

Hey I rely on the record during play to generate steps heavily (EVERY SINGLE SIMFILE I've done other than when I was creating files in notepad from scratch). Usually I sync up a file with dummy steps then I select the whole range of the song, go to a certain quantization then press arrows as if I were playing it in my head. Sometimes I have to re-do the whole thing. Then I clean up all the quantization problems, add/remove steps here and there possibly add more jumps, even out all the HOLDS, add mines if I want them. Sometimes I even re-do a small section, but I heavily rely on this feature to get the basis of my step charts.