Thread is just as efficient based on the few battery operated motion sensors I have. That’s another reason Matter over Thread is better than Matter over WiFi.

I personally won’t buy another IoT device unless it’s Matter over Thread.

With that said, if you already use home assistant, and what you have works well enough. I wouldn’t rush to upgrade. But I would choose Matter + Thread over older technologies moving forward.

If you want to move to all HomeKit, then the upgrades are worth it.

In an ideal future world, Matter + Thread devices won’t need a vendor app to work. They just connect to your Amazon Voice assistant, or your Google Home, or your Apple HomeKit setup directly. (Or Home Assistant)

In the future we should see more vendors selling Matter compatible devices that don’t even offer an app. But this is down the road.