No, this is incorrect. That fonts.conf fragment changes the default sans font to BPG Rioni on all systems, not just Georgian ones. This isn't acceptable, since the quality of its latin characters is worse than in the default font. There's a couple of issues here:
1) the fonts.conf fragment is malformed and so works unconditionally
2) fontconfig fails to recognise the BPG fonts as Georgian. I can fix this easily.
I'm working on point (1), but it's more awkward than expected.