If you use one of the AI static instructions methods (e.g., .github/copilot-instructions.md) and tell it to not leave the useless comments, that seems to solve the issue.
I've been intending to try some side by side tests with and without a conventions file instructing it not to leave stupid comments—I'm curious to see if somehow they're providing value to the model, e.g. in multi-turn edits.
it's easier to just make it do a code review with focus on removing unhelpful comments instead of asking it not to do it the first time. I do the cleanup after major rounds of work and that strategy seems to work best for me.
This was not my experience with the earlier preview (03), where its insistence on comment spam was too strong to overcome. Wonder if this adherence improved in the 05 or 06 updates.