Many people dislike the cloud-focus of sonos. When they started, the primary use case was streaming off of SMB shares, but now it's streaming from cloud providers. Given that all of your music is coming from the cloud, is it really that much of a stretch that your sonos hardware is heavily backed by cloud services too? It really does help ease-of-use for non-technical folk.
Ironically, Sonos wreaks absolute havoc on my Unifi network when I hardwire the Sonos speakers (I have 12). When I remove the ethernet cables, it comes so unreliable, it frequently loses connectivity while playing music or speakers straight up disappear.
I do have over 100 devices on the Dream machine + 4 AP-HDs network, but Unifi promised to make my network rock solid, and it's been anything but.