Sonosnet vs Wifi - which is best?

I have a router and 3 extenders across my house, so my wifi is excellent all over the house and yard.  If I hard use a Bridge/Boost or hardwire 1 speaker in, is that hardwired component the only one that pushes out Sonosnet?  If so, I would think my own wifi network if probably stronger / more reliable than the one source for Sonosnet.  Toughts?  

BTW, I plan on adding over 5 speakers, and a home theater setup.  Will I be forced to use Sonosnet?