I don't know, I manage a PHP app with about 10K users. If it doesn't cost much more, just paying to have the peace of mind that I never need to think about it again as my app grows, would not be a bad trade. This is assuming, of course, that the price is not extortionate.

In case it scales to Facebook's scale. Better safe than sorry.

Possibly a game server? Between matchmaking, leaderboards, achievements, you'll never be updating 10k rows at once...

I work with a lot of financial services applications, and they are most definitely in the "simple CRUD" with regards to the database realm, but with extremely high throughput and multiregional.

Having it be Postgres compatible is the big selling point.

Who else would use it? Not sure, gaming perhaps?