For that $10, I get database backups, custom domains and no idea what team projects are, but I can add others to my project. On top of that, I also get everything else that firebase offers... task queue (PubSub), log analysis, hosting, realtime database, analytics, ability to hire someone who knows firebase/gcp, google's entire devops team.
In order to get a bit closer to that level of features, I'd have to bump up to the $39/mo plan. While I appreciate the competition, this doesn't compete for me yet.