Of course, there's no guarantee for future products, but once they're set up they're not gonna change unless you go in and update their firmware.
I think if these had Z-Wave they would have cost a few dollars more each, due to licensing. It would be nice because I do have a Z-Wave mesh up and running alongside a zigbee mesh and a few oddball Wi-Fi only devices like these shellies, but they work well enough with home assistant that I don't consider to be a drawback yet.
The only thing I wish they could do better is expose more of their configurable options via whatever API they present to home assistant. A couple of these devices speak mqtt which opens up a few more capabilities, but there are still many fine-tuning aspects like controlling the way a switch attached to the device functions, i.e. whether it behaves as if it is detached or functional - useful with toddlers around) are invisible unless you are using the built-in web configuration page.