"in many cases"
Yes there are occassions where this is needed because WiFi won't work or cables are difficult.
I alluded to that in the OP.
But we do need proper standards testing of these, which doesn't exist. At the end of the day if the designers can't make them work correctly then we need a different solution. The Radio Spectrum is assigned and protected by National laws and International treaty.
It may be that these need an allocated band. Or limited to the difficult buildings (which often block the transmissions from leaving the building).
Most people don't need them. They do pollute the Spectrum, especially some models/makes. Since some are much worse than others it suggests the correct standards and testing is not getting applied.