* It can replace the free licensing for cheap tablets which had fairly extreme hardware restrictions so normal laptops couldn't use it. These restrictions probably had the unfortunate effect of giving the impression that Windows was unusable on tablets because these devices had to have limited RAM to be eligible.
* Now, they can give free or cheap licenses to devices with any specs, but get the payment for a full version later if the users want it. This way they can compete with higher-end chromebooks.
* By preventing users who aren't tech savvy from installing junk that will clog up their system, they can actually give them a better experience.
* They can give developers yet another reason to put their apps in the app store, even if just using their new conversion tool. Maybe there's still hope that people will actually use the app store!
* Because the upgrade goes right to Pro, rather than Home, for $50, this actually isn't a bad deal for individuals who want Pro anyway. Currently I think that's actually more than a Home->Pro upgrade. I imagine they'll fix that, but even if either upgrade route is the same price, the OEM cost for the 10 S license should be cheaper or free so, it might be cheaper to buy a 10 S computer and upgrade.
Still, from a user's perspective, Microsoft locking down the OS and trying to force people into the Windows store doesn't seem that reassuring, and if you can't use WSL I probably wouldn't want to use 10 S anyway. I might buy one of these laptops and install linux, though.