The Rufus author has capital O Opinions on this: https://github.com/pbatard/rufus/wiki/FAQ#user-content-Blah_...
Yes, you can get Intel NUC and yes, it does support NTFS in UEFI. It is also compliant with UEFI (i.e. "can"). But is is completely useless, if you are shipping media, that should be bootable by 100% of UEFI-using machines. It is usefull, only when you are targeting such machines specifically.
You can ship your own filesystems, volume managers, device drivers... but they should be signed with a key trusted by Secure Boot, if you want them to be useful at all. Most users are not going to disable SB for your snowflake of efi binary; especially if it is OS installer.
As a result, nobody (nobody in Spolsky's sense) really bothers. When you are shipping bootable media, fat is good enough. It will boot your binary, do stuff it is supposed to do, and everybody goes on with their lives.
We have very different experiences, I must say. Mine is that Linux installers that do support Secure Boot are having to go out of their way to point that out to users because people are just disabling secure boot as step 0 by default.
Heck, NTFS is more commonly supported on UEFI implementstions than exFAT is, even when there is no free (as in gratis) implementation of the former, but there are several for the latter.
He literally addresses that. Saying that the one thing the Spec does is require that, at the very least, you can boot from FAT32.
When he says the spec doesn't require FAT32, he means nothing in the spec says your device itself should be FAT32 and that it's fully conformant to use a UEFI:NTFS driver to load from a USB stick.