I can't read anything from that website but I trust you. It's been a while I am away from debian based distro and digging a bit : the problem is not that you need a ppa but you want the very latest version of the driver. You can have your reasons for that.

Mesa drivers are properly packaged from debian and forks alike. Going out of this way to install package from unknown people/org has its risk indeed. If newer GPU/graphics chipset would need newer driver I still make a point that this should be the manufacturer responsibility and not community to work from opaque implementation.