> (This assumes that the tradeoffs are of the magnitude that they only manifest impact at scale, hard to address that without concrete examples though)
The tradeoff is usually flexibility. You run into flexibility problems anytime requirements change. Scale doesn't factor in.
If that assumption is true, then it follows that the same argument used in the last statement also applies— that if you're not at massive scale, then its likely the aforementioned tradeoff of not using RDBMS is likely de minimis.
(This assumes that the tradeoffs are of the magnitude that they only manifest impact at scale, hard to address that without concrete examples though)