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.
For those panicking about it, this is not something you need to worry about. Here’s what this actually does:
Enforce the use of GPT partition tables for all UEFI-based Fedora installations for x86 architecture. This removes support for installing Fedora in UEFI mode on MBR-partitioned disks on x86 systems
You probably have already been using GPT on your UEFI system since you had a UEFI system. Even if you somehow were using MBR, this probably;
Won’t break existing installations, as it’s merely support for installs of this type
Would not be a problem even if somehow the broke existing installs, as it’s not difficult to convert MBR to GPT.
As I’ve commented elsewhere on this post and others have said, this is a change that affects pretty much no one. I didn’t even know MBR (legacy BIOS) partition tables on UEFI boot was possible, honestly.
By no longer putting in the effort to maintain this bit that no one uses, work can be put to something someone uses.
Also, with Linux, specific distros can get encrapified (kind of happened to Ubuntu), but as others have said, there’s usually always another distro to jump to at worst.