Honest question: why are off tracks part of Safety Rating?

I am a bit baffled at how severe off-tracks are on Safety Rating. I personally do not have time to practice much, I will therefore go over the limit here and there. How does going 1 inch off track in the gravel make me a more dangerous driver?

The reason I am asking is because I am trying to get to A license to try IMSA but unfortunately hit a hard wall at B license, haven't been in contact for a good 10 hours of racing, and yet, because I will have an off track once every 3-4 laps, my Safety Rating is going straight down.

You will tell me, just practice more, but I just don't have the time. I do not believe I would be a hazard on track if I was to make to IMSA, I would just hurt myself by making small mistakes here and there.

Don't get me wrong, off tracks should definitely give you a slowdown penalty, but why have it affect SR?