OK, I err.
Due to the fact that the 7/8 X 14 thread will fit into a single stage press allows that fact to be true. If you want to stick that die in a single stage press and powder your cases that way, I won't keep ya from it. I find the operation goes faster using shell blocks for rifle or pistol when using a single stage press.
To each his own.
It fits due to standardization, but not designed necessarily to be used in a sigle stage operation.