No. You can automate during recording if you have a controller of some kind. (ie: mixer/keyboard/pedal)
Danny's video was showing while I'm reiterating how to if you don't have access (at least not the physical controllers or you don't feel like fighting with the mouse.)
This is essentially editing like you would via notation or PRV if you made note/velocity/timing or such like errors. Now, if your errors were quite atrocious, you may as well just re-record it, but automation can be re-applied as well.
However, it's much easier when it's done afterwards, especially if you're of the meticulous type. (*Raises Hand*) And again, you don't have to deal Crop/Cut/Copy/Paste often if at all - especially if it's a complex composition/arrangement. (*Raises hand again*)
Don't get me wrong, retakes are wonderful; however, I'd rather take one or two takes automating afterwards than scold the instrumentalist fpr not having faded when s/he should have or if I think one would fit, but rather not bother him/her about it.
The advantage to this is the illusion created when done, ie: Songs that fade. Are the musicians actually fading or is the engineer adjust the fader accordingly? Live play is somewhat different, but if the house mixer is present and it's being recorded unless coming to a dead stop is the intention, automation - fading - will happen.
As I said before, this is one way to allow tracks to breathe (employ dynamics) and have happy musicians. ("I get a break! Thank you!" Then, they're playing two seconds later or forget when to come in and throw everyone else off. You don't want to deal with this!)
Music isn't stubborn. Musicians, OTOH ... (I mean this in a playfully sarcastic manner though many could attest to this)
Just like Bit said, that there's no reason to record hot, there's no reason to automate while recording, but again, not everyone is meticulous by nature. So, it's up to you, but I recommend doing so after recording. You can always fix mistakes later.