There is, unfortunately, a lot of uncompensated work asked of teachers.
Any application that requires a reference (job, internship, licensing, etc) will require that reference.
I don’t see value in speculating someone may not be a good writer. Adcoms look for the info LoRs do provide. And they are good at looking for the salient points, if any. What do you seriously propose? Earlier, someone said just offer them for borderline or sleeper kids. Even so, you could get a poorly written letter.
More difficult is kids who provide letters from teachers out side their interests, from years ago, or not academic, at all.
This isn’t the thread about teachers closing the gates- that one stuns me. That’s a poor school policy.