So we know hearing aids don't damage hearing any further, how about streaming on them?

No, otherwise it wouldn’t be an option. It’s no different to wearing headphones etc, except we would have these at higher volumes as I did which would have damaged my hearing more. Being able to stream music etc using my hearing aids, Oticon Intent means I can keep the volume at a more reasonable level.

I am trialling Lumitys, Intents and Nexias. I have just started streaming (my previous aids couldn’t do this) and had the same question.

What I’ve found (no surprise really) is that the volume level I have on my mobile when I am streaming is really low, whereas when I wore connected earbuds (no aids) I had to have the volume at a level that was in the “danger” zone as far as the mobile device was concerned (which meant it kept warning me the volume was high). So that confirmed for me that it should be pretty safe.

Interesting discussion and something that I have long wondered about, using HAs for almost all of my life. Obviously, those silly phone warnings (and the way their volume is clipped by the authorities) do not apply to people like us. Still, I worry about listening to music at very loud volumes using other means.
Probably such risk depends on the mechanism of hearing loss of the individual and how that might synergise with lifestyle risks. That mechanism of initial loss depends on what caused it: ototoxic drugs (esp aminoglycoside antibiotics in kids, my case), old age, exposure to loud music/trauma or genetics.