It can be more than superficial. If you’re restoring files from your old PC to your new one, it could make a mess of things if the user account is in a different path. Probably not a lot of people write scripts for their windows PC, but those could break.
Sure it would be a janky restore or janky script if it was explicitly specifying the path of the home directory instead of the environment variable. But environment variables have been janky in the past on windows, so it’s best to just keep the paths as consistent as possible when migrating to a new system.
Kinda shit they just wouldn’t prompt you for what you want your home director called tho.