I’m probably wrong but I’m wondering if it’s due to configured languages. In my profile page here I can choose what languages to see. It gives a warning that says deselecting “undetermined” will result in me not seeing most content, but I don’t have an option to select undetermined. Maybe that’s default not-selected and not visible so I’m not seeing anything post or comment whose language isn’t explicitly set as one of the ones available for me to select?
I have both and use them with home assistant. Personally I don’t have a preference and I just get the best device for my needs as long as its one of the two technologies. The only knock I have on zigbee is one of my sensors likes to continually drop but that’s probably a problem with that particular samsung sensor and not a problem with zigbee as a standard.
As far as HA integration goes, I don’t think either is better than the other in my experience. They both work perfectly (other than that one sensor) and were easy to setup. Personally I’d say figure out what devices you’re likely to want in the future and then see how many are on zigbee/zwave, their costs and reviews and availability, and just choose one. Can always add the other later on for relatively little money if the need arises.