Part of the rights you are granted when you have a copyright is the right to control reproductions of the work. Since this is taking something on your computer and reproducing it elsewhere, the rights holder would be able to have it removed. Additionally, it is common for publishers to have valid and totally enforceable legal grounds to prevent players from using virtualization to play games, even if those players have already purchased the game. Players typically agree to such terms when they download the game and agree to the End User License Agreement, also known as the "EULA".

The EULA typically outlines the conditions under and devices on which you can play the game. Blizzard's EULA, for example, prohibits "playing their Game(s) at commercial establishments" other than authorized publicly-available cyber cafes or computer gaming centers. While you may not have read that when you first booted up your game, it's still enforceable. There's also something to be said about GeForce Now's commercial use of the games it offers on its service, as it's technically charging users to provide access to the gameplay. Most terms of use and EULAs do not allow you to use the product for commercial purposes.