Having cabled my apartment with Cat 6 definitely made me prefer fiber, it would have been a breeze instead of pulling thick cables from my office to other rooms. Cat 6 also shouldn’t be bent or you risk it going out of spec, and modern fiber nowadays have bend radius comparable to (or even smaller than) Cat 6.

I see how sloppy some FTTH installs are and they all work fine, and this is for light that travels for long distances.

The only advantage copper has is PoE.

You'd be amazed what exists on the market these days. For example, the pre-terminated InvisiLight fiber cabling is 0.6mm in diameter and has a 2.5mm bend radius. I've personally installed this cabling while making many 90 degree (and sharper in some cases) bends without any issues. That makes it easy to hide and trivial to fit right through doorways and other tight spaces too.