It's one of those "just because" moments. The idea was to future proof my home infra for a 25G NAS connection. Most ethernet connections tap out at 10G. While theoretically speaking Cat 8 cables can do 40G, hardware support for full 40G Cat 8 NICs is rare. Fibre is very very flexible with its potential bandwidth and SFP28 transceivers are relatively affordable (if you don't do what I did by using SMF. Home networks should only use MMF if the property isn't a mansion.)

I still prefer SMF over MMF. It also allows me to "move" where the city fiber comes in and patch it to another location without any active hardware. So I can for example move my router into another room.

I ran SMF and have no regrets. https://sschueller.github.io/posts/wiring-a-home-with-fiber/

I'd say the opposite - any fibre in a wall should probably be single-mode fibre (SMF), simply for future proofing. Single mode optics aren't much more expensive and single mode fibre hasn't changed nearly as many times as multi-mode. You can run 25G over the same SMF that once ran 1G - not so with MMF.