[meteor dev] Meteor treats the server as an environment for running arbitrary privileged code. You can write server-side logic that consults third-party services, logs client writes to a separate audit trail, keeps authentication state between requests, or implements complex transactions across multiple tables. Similarly you can write code to run periodic database updates on an interval, or respond to incoming HTTP requests from other clients.

Not all apps need this stuff right away, of course, and some never do. But it's hard to do these things w/o a secure server environment for privileged code.

And then of course there's the usual tradeoffs between having control over your hosting environment (a la Meteor) and outsourced backends as a service (a la Firebase).

We're big fans of Firebase, BTW. We think more databases will move to a realtime model. Excited to check this out.