See, this is why you should not believe Wikipedia.
The DOS syscall interface has no concept of an EOF character. ^Z being considered EOF was a feature of the COPY command, later replicated by the runtimes of various languages targetting DOS.
Not just DOS. CP/M also used CTRL-Z, principally because file lengths weren’t stored on disk - just the list of 128-byte blocks. So to get granularity beyond multiples of 128, you need an explicit EOF character.
I think TYPE would also treat ^Z as a terminator of the file. I think it was common in DOS to have binary files with a textual header followed by ^Z, that would hide the binary part.