I've never actually considered this for the house.
Do they all have to be the same company? As I recall from a while back (and info may be outdated) there is no single standard...so each switch could be a different company and may not mate with others propertly?
Good ol Kevin has switches and lights in this house I still don't know how to turn them on, or what they do after 2 years. I've got 2 lights at the driveway...no clue how to turn them on.
I have a mix…Genii and these Costco ones. From what I see some manufacturers can all be controlled by a common app but some are outliers. Haven’t looked into amalgamating them all. I can deal with two apps.