Does Atom support anything besides x86? Does the editor actually need to run on a 64-bit architecture, or is that just the only one that they produce official builds for?

I don't know off-hand any software specifically built for aarch64 that couldn't be compiled for aarch32 as well. I'd be interested in hearing about it though, and what 64-bit provides that 32-bit doesn't, when we're talking about a device with under 4GB of memory anyhow.