[aqme28]

But if the metric is "need in most cases," then that's fine. You don't need an embedded database in most cases.

[ellimilial]

The other way around. For most problems you don't need a DB. Only for the subset of those that do you need a dedicated process/container/machine.

We have learnt to use full-fledged RDBMSs as a default because they proved really flexible and powerful over the last 30+ years. But they do have limitations and cost.