In larger homes where Sonosnet can't reach all the devices or there is a lot of interference, it is not an option.
Sonosnet was only created because of the target audience = the average Joe. And the average Joe's all-in-one service provider box SUCKS! Hence the desire for SONOS to come up with something of their own.

Most all my installs, I'm upgrading the network as well. So I turn Sonosnet OFF! Wire all the units I can and the customer's PLAY speakers on WiFi.
Is there an issue with firmware updates turning Sonosnet back on? Causing an STP problem? I haven't seen that yet, I don't have a ton of SONOS systems out there. None have had problems in the last few years.