Quick question: Up until now, to use UE-V or App-V you had to have the System licensed with a Volume License Windows Client with the MDOP. So basically, you are already licensing the enterprise version.
You could simply choose to be lazy and not re-image that new system with pre-installed Windows 7/8/10 Professional Edition. Which is silly.
Especially if you are already running Windows 10, as you will be giving up Credential Guard, among other security enhancements.
So.... why are people really bothered? Because now they have to pay for what they use?
Up until now, you could for instance license 1 Windows Client with SA & MDOP, and use the MDOP bennis - such as App-V, MED-V, UE-V, DART, etc - on aaaallllll those other little boxes you bought from the bay, with that preinstalled Win 7 Pro. Not quite legal.
Integrating the UE-V and App-V Clients into Windows 10 is basically just 2 MSIs less to deploy. You still need to run the respective servers and infrastructure in the backend.
One last sidenote: MS needs to make it easier to license SA for SMB. IF those SMB have a Volume Licensing Contract, they usually have an OpenValue - at least in Merkel-land - and those lock you in for a year, or even three for any purchase. Adding a single SA for a new PC that you just bought is close to torture, especially if you are already in year 2 or 3 of your 3-yr-contract.