I was wondering too why anyone would ever want this…but the proposal explains it:

Support for UEFI on MBR was originally added in blivet#764 to accommodate cloud image use cases, such as AWS, which at the time did not support UEFI booting on GPT disks. These constraints no longer apply to modern cloud platforms, making MBR-based UEFI setups unnecessary for current Fedora deployments.

So basically it was some workaround a few years ago. I have a hard time to see any reason speaking against the removal.

On-screen keyboard was already mentioned, but there are some other small things that might be useful for some:

Reboot/shutdown without having to login (Your husband/wife/partner can shutdown your computer without first having to login and be greeted by the porn folder on your desktop…nah seriously, this can be useful at times when your turn on the computer, get called away and someone else can easily shut down the computer after you didn’t return for some hours)

Keyboard language selection before password entry. Very useful in multi-language households/companies.

The WM selection also allows kiosk-like behaviour in special cases…like you don’t start a WM but start in kodi media player for a movie evening or you create your own WM session file for a single game that runs as soon as you login.