Points 2 and 3 are moot in the era of ext4 and zfs.
Not sure what their strategy actually is here.
The number of exFAT filesystems is large. (Perhaps not as big as FAT32, but on the other hand it has fewer limitations.)
So having ExFAT natively supported and having better performance is great for everyone.
Also by spec SDXC cards come formatted as exFAT filesystems and this change means Linux can now be compatible with them without requiring reformatting them with another filesystem.