Xata employee here. The clarification would be "platform" vs. "host". You get a lot with Xata beyond the core Postgres offering. We automatically replicate to OpenSearch for a great, fast search experience, provide file attachments through the DB itself (with image transformations), provide a pretty cool editor, and are now starting to think heavily towards how migrations could be better (more on this next week). No knock against Neon, who build cool stuff too.
I agree "only" is likely a little aggressive, but marketing is tricky and sometimes the A/B gods appear. We've switched this one-liner a few times in the past year. I'll provide that feedback to the team in any case.