Hi.  The linein becomes just another source and can be played to any speaker(s) in your system.  If you used the line-in on a Five, for example, you could even play your turntable to your HT setup and play a different source on your Five.

I have my rega P-25 streaming to all my sonos devices. Just plug the pre-amp output into the Sonos Port input and you are good. As ppl say, the port is “overpriced”, but since it’s less than my cartridge….