It's not backwards compatible, it's just Node compatible. Demo is not, and it's stated as much clearly. Thus the suggestion that bun is more backward-compatible than Deno is incorrect and speaks to a fundamental misunderstanding of the two projects.
Sure, a poor choice of words. Node compatibility is what matters to me (and likely many others) practically as a node developer. Deno's benefits don't outweigh the costs of migrating to it and adopting it more broadly, in my opinion.
tried deno briefly the other day, was a real pain. just wanted to hash some files. they had an std hash lib but dropped it in favor of web crypto which bazzarely doesn't have a hash.update method for streaming?? not very good. prefer node's impl