This is not a reason to prevent switching, quite the opposite. Encryption is an awesome thing, and should always be used. It also inevitably causes slowdowns, but the best case is that it’s practically nonexistent of a performance hit. Not a lot of Linux distros let you set up luks root encryption in the installer, and it’s still pretty tricky to setup. But also if you’re using Linux, you should always be using luks encryption if you can as well.