But don’t WAPs require a hardwire connection back to the router?
mmm, sort of – the backhaul isn’t a requirement for mesh and is just a mechanism to get around the range extender problem of talking to devices and the other routers on the same channel, however as mentioned it does make setting up the expensive new network easy without needing cables….
using access points hardwired avoids the same issue but most aps can be configured as range extenders if you don’t mind the bit of a performance hit
mesh has the advantage that the aps can participate in handoff between themselves as you move a device around the house and reduced switching times, in reality most people don’t require this as your device should cope quite happily on it’s own :-)