Instead UEFI is a whole OS of its own.
I work regularly with servers that provide most or all of what EFI does, and within the console, though these servers provide it with considerably less confusion and hassle.
Having an embedded console can be very handy to have a functional operating system available in the firmware. Whether this is troubleshooting the server, or the boot process, or baseline server configuration without having to fire up an operating system or a diagnostic.
What's not so handy (with EFI) is the complete grab-bag user interfaces, nor the confusing array of consoles that can exist (the Shell, the menus, the BMC, and increasingly often a management widget), nor limitations around the callbacks. And the byte-code engine concept that was intended to avoid having to implement console (and boot) drivers for each new widget never really got traction.
Simply having boot drivers available as callbacks for the operating system would have been very handy for folks writing or porting an OS. Debugging in the bootstrap environment stinks.
IMHO, EFI just isn't a well-designed user interface. It seems to be a scatter-shot collection of pieces that were duct-taped together into a technology demonstration. And I'm not entirely certain the folks that originally built EFI ever intended the manufacturers present it to the end-users to use it as the primary console, either.
Two words: EFI Shell.