This is rather a moot point, as you cannot (yet?) stream 24 bit files from any streaming service on Sonos. 

Oh really, I misread this information then.

https://support.sonos.com/s/article/79?language=en_US
 

It says that 24 bit is supported in S2, so what does it mean?

What it should say on that page, and you’re right, it doesn’t (yet), is that 24 bit currently is for local streaming only. This was covered in the announcements thread, which you may not have seen, I’ll try to go find it and post a link for you. But I certainly agree that FAQ page is misleading. 

Here it is:

https://en.community.sonos.com/announcements-228985/introducing-s2-new-app-and-os-for-sonos-6841762

First post, under High Resolution Audio

Now to get Sonos to update that FAQ to be more clear....

Thanks Bruce for the information. All clear now.

You’re most welcome. I’ve put in a request to make that FAQ much more clear. We’ll see if that happens, but I completely get why you came up with that conclusion.