Hi Werner,
Pls take a look at this topic.
Me and Robert bought a SmartLock 4 (non-pro), and as we discovered, Matter already worked without unlocking it for €49 
Maybe it still is sold like that!
But I would’ve bought the Pro for €50 extra, instead of a non-pro-with‐a-Matter-unlock-fee-of-€50
We both do not use the lock with Homey Pro, but with Home Assistant.
It should work fine on the Pro 2023 though, the only functionality for now is lock & unlock, and (probably) battery level.
Robert got the experimental ‘open the door’ functionality working, so it should be available @ Homey one day, when Homey Matter starts to support it.
The pro version additionally has onboard Wifi, rechargeable battery pack, 5V charge connector (can be connected permanently), and somewhat fancier looks
