the use case for this is basically zero, since the community prefers implementing their own subcommand systems instead (which are much more flexible).
In addition, allowing spaces in command names makes it extra complicated to display helpful information to the user, such as the command that was actually accepted by the command map (which would be useful for identifying accidental invisible characters / control characters when sending commands).
this makes translation usage much more statically analysable.
The only places this isn't used are:
- places that prefix translations with colours (those are still a problem)
- places where server/client translations don't match (e.g. gameMode.changed accepts different parameters in vanilla than in PM)