Greek here, mobile phones are non-geographic but used to be service provider specific, but even this practice isn't applicable due to number portability.

Landlines used to be geographic but this isn't relevant any more again new to number portability.

I mean non-geographic within the country. As far as I know, the US practice of assigning mobile numbers to 'area codes' is unique.

Yes. I was broadly agreeing with you.

Just saying that some countries are small enough that it's essentially the same.