It's never recommended to change DE's that way. To quote the article "It is recommended to use the ISO for a specific desktop environment". However i3 does not have its own edition so this is obviously not an option.
From memory it explicitly forbids doing it with Plasma (KDE) because there have been several issues that were only encountered by installing other WM/DE's alongside Plasma, creating a support headache, so users were instructed not to do it.
Of course its your computer, no one can stop you from trying. Just don't ever ask for help with anything for the life of that install because you are then in an unsupported configuration.
