> when there are other cars around that would need the indication

This has a failure state of "when there's a nearby car [or, more realistically, cyclist / pedestrian] of which I am not aware". Knowing myself to be fallible, I always use my turn signals.

I do take your point about turn signals being a reminder to be aware. That's good, but could also work while, you know, still using them, just in case.

You're not the only one raising that concern here - I get it and am not recommending what anyone else should do.

I've been driving for decades now and have plenty of examples of when I was and wasn't paying close enough attention behind the wheel. I was raising this only as an interesting different take or lesson in my own experience, not to look for approval or disagreement.