Something like phtn.app really should be the default

Disclaimer: Photon is great and the dev does a fantastic job.

However, there as still issues induced by not using the default UI. One of the instances I used added photon as p.instance for a while

Photon was still in early stages, and there was a bug preventing it to load for some people (Firefox users IIRC). In the end the admin switched to Tesseract.

lemdro.id has photon as a Default, but it took them a while to the latest version, for quite some time it wasn’t ideal. I would still go to l.lemdro.id just because the Comments view was available, or because some other info was missing/hidden.

Lemmy releases new versions quite regularly, and there are usually a few bugs. Photon development is independent, and the Photon dev has to catch-up with those. Add admins sometimes limited availability to the mix and the experience can really become subpar.