Sometimes I like to go back and play old stuff too.
Now, this isn't to say that Wine is totally up to par with Windows in terms of compatibility, but performance hasn't been a significant issue for quite some time.
This might be enough of a barrier to stop me using it right now.
I do not see a performance penalty at all with WINE. Most games that work play at speeds matching or better than windows. WoW is usually a big example of that, as are emulators.
Running either in wine is a fine benchmark on performance.
I initially had that problem, but it seemed to be the fact that (on top of some phoning-home options that I missed disabling originally, which seemed to play some role in the slowness -- disabling them helped) the Windows 10 update from Windows 8.1 also, for some unknown reason, rolled WLAN drivers back to the versions that were several years old (pre-Win8.1 at least) and fairly broken and couldn't automatically locate new ones; redownloading the latest (for Win8.1 -- no Win 10 specific drivers were available for the hardware in question) drivers (which is what had been installed prior to the update) resolved the slowness problems.
Steam OS is a Linux-based OS designed primarily for gaming. Any and all cloud-integration will be specifically gaming-focused.
Can you not see the difference between that and a general purpose OS like Windows harvesting data everything you do on your system?
I won't be using Steam OS to do anything very sensitive like sending or receiving personal e-mails, editing word documents or spreadsheets, or browsing the internet for whatever reason.
Unless you consider firing up a shooter or a city-building sim sensitive.
The two OS's have very different purposes and use-cases.
There's a big difference between 'allowing' and 'requiring'.