That is exactly how I slice mine as well.
I find that too much brisket fat gives me horrible indigestion, I figure it does the same for my family and guests.
Also to your point (no pun intended), without separating the point/flat, I can't slice across the grain for both pieces, so end up with a more chewy end result.
To me, when I'm presented with the point/flat slice still connected, the fat between just looks gnarly and unappetizing.
With a full packer, for me, slicing this way maybe adds 5 minutes max to overall slicing, but I think presentation and tenderness of the final product is so much better!
Regards.