You're pushing to B2 though. That'll cost a pretty penny for how much data I need to store. Come to think of it though maybe I could push to a disk attached to a Windows machine, which would then back up to Backblaze. Awkward, but seems like it'd work.
That's very likely the reason they've not bothered with a Linux client yet. I'd bet the typical Linux user has a hell of a lot more data than the typical Windows one.
I use B2/restic and only selectively backup things that are either irreplaceable or I'm willing to pay for. It costs me around 1 USD/month, which is only ~200GB. I have a lot more data than that on my NAS!