The cloud is not reliable and it means you have to have your daw computer online. Most studios don't allow their machines online. And a machine license restricts you from easily moving your asset to another machine - again the computers would have to be online.
I've used machine licenses for years and they have been just fine.
Had it happen where if I make a change in my system the machine license goes south. Besides if you want to use a licensed plugin that has a machine license on another machine you've got all kinds of hoops to jump through. Not so with an iLok or Vienna Key.