[barrkel]

Almost.

More that being forced to separate church and state, forced to keep business logic separate from database manipulation, and forced to go through an abstraction interface, then lets you leverage the interface later if and when the database becomes a bottleneck.

It's a devil's advocate position. I actually think it's unrealistic and probably not worth it at the time. The forcing function is what's useful, not the database portability per se. And whether it's actually useful depends on being so successful that you have so much data that your regular RDBMS can't cope with some access or update patterns. That's a hefty bet early in anything, and probably doesn't make business sense, until it does, then you wish you did things differently.

(Not coincidentally, it's a position we're in at my workplace; the database has hit its limits and we're needing to use hybrid approaches to hit latency NFRs.)