Matter devices should be able to use your current wifi if that’s their network. Otherwise it would use thread similar to Zigbee. I’ve only looked at the ZBT2 as a thread router for connectivity to home assistant so I don’t have a lot of experience here yet with thread but I’ve been using Zigbee for years. Yes thread or Zigbee can interfere with 2.4ghz wifi as they’re in the same band, but my experience is the opposite: wifi has a bigger effect on them then they do on wifi. Zigbee and thread are designed for low power devices so they’re easy to drown out.
I don’t know if there’s a feature difference but I don’t think there should be. I’ve used matter devices on my wifi with no issues and didn’t need a separate router, and when I pick up a thread device I’ll use a zbt2 as the hub.
I have air quality (Apollo and AirGradient both running esphome) sensors in a few places in the my home and use them to automate some ESPHome-converted Levoit air purifiers. I also have an AirGradient Outdoor sensor that I use to at least tell me the air quality is bad outside. I do use the outdoor sensor to notify me about opening door and windows to help cool the house (when the outside aq is ok).
My house is pretty well sealed so that’s benefit and a curse - the outside aq doesn’t affect the inside too much, but things like cooking need the air purifiers turned up to really clear. The charts from activities inside give interesting insights.
Wildfire smoke is a yearly occurrence here so I’ve had this set up for a while, I just keep adding to it.