I don’t want to double post everything, but today Apple announced a bunch of details of how they are going to handle matter.
Essentially they are going to build the matter support into iOS, and you get to it through the HomeKit developer platform.
Other smarthubs, potentially including smartthings, could use this platform to create their own app that then brings in matter devices. The matter devices would show up in both the HomeKit app and the smartthings app. It’s not a perfect integration, but it’s very cool.
And of course it’s only available to those with iOS devices, android users would have to find another alternative.
More details about how Apple is going to handle it in the following thread: