Improving in chess "until you stop hanging pieces...no improvement"

This has been said many times by various chess YouTubers and coaches. I just wonder - what if I just can't get rid of this old habit and keep hanging pieces time to time, but nonetheless improve my chess understanding, polishing off my tactics and even strategy. Hanging a piece is not really a problem of not understanding a concept, if we think about it. It is a matter of playing in a haste or just forgetting. So hypothetically, I can understand as much as a grand master, but still preserve the habit of hanging a piece, say once a game. Let's say I am old and really can't remember to look at all the pieces at all times. However, I is still possible to win most games by crushing your opponent with constant tactics and good understanding. Does it make sense or is not hanging pieces just a crucial part of understanding chess conceptually?