I suppose you could just use insert link and all it'd require is an exclamation point edited in at the front, but a dedicated button would be nice for those that didn't know that was the formatting. I didn't know myself until this thread.
I'm glad I did though, now it'll be easier to add images to my comments!
Since I got my Steam Deck, I think that was 2 years ago or so now? But I also ended up using it on my Windows PC to replace Amazon, Gog, and Epic.
It's not perfect, but it does the job and means I don't need multiple clients.