In the US, I don’t know of any code requiring three way switches except for stairways. That’s left up to the individual homeowners. And even for stairways, there’s an exception for sensor technology:
“Exception to (a), (b), and ©: In hallways, stairways, and outdoor entrances, remote, central, or automatic control of lighting shall be permitted.”
The one exception is attics, where some local jurisdictions do require a physical on/off switch at the entrance to the attic for the lights there (although it can still be a battery operated switch, at least in most places) But other than that I think it’s just considered a convenience issue, not a safety one. As long as the lights come on when someone is at the top of the stairway, the US code does not require that there be a physical switch there. ( again, except for attics in some jurisdictions.)
Personally, I think it’s a good idea, but options like the Lutron pico’s or other battery powered devices that would still work even if the hub were not operating, including contact or motion sensors, seem fine to me.