trying to HLE everything is actually more hassle in the long run and will only lead to people writing bad code for the system that doesn't stand a chance of running on any real machine.
In this particular case, HLE is something I can afford. After all, most C65 owners care more about the integrity of their hardware than they do about running software on it, so they will keep it locked inside a glass cabinet and never turn it on. Case in point: last year I went to a retrocomputing exhibit where I've been able to see and touch a C65, but when I asked the owner to switch it on, he refused because "some circuits might get burned". Another retrocomputing enthusiast told me just today that he likes collecting original machines, but he always ends up running the software on emulators because they are far more practical. So, if people start writing C65 code, the probability that that code will ever be loaded on an actual C65, with its quirks and bugs, is extremely low
Although, if we were talking about a C64
emulator, I would agree about your position on HLE, because of the abundance of C64 software that exists, that must be run on a low-level emulator because it exploits all kinds of quirks of the original hardware.
But I'll never make a C64 emulator anyway: considering the quality of those that already exist, I'd be just reinventing the wheel.