I think there are a few things to note here.
1. There are regions of Texas, largely in the North East where chopped brisket sandwiches are quite traditional. Most likely, it was both brisket and clod that was smoked then chopped.
2. The two major flaws of any brisket cook, overcooking and undercooking, can be adjusted by chopping. An undercooked brisket will be tough, and dry; overcooked will be falling apart and if really badly cooked, dry. By chopping the point and flat together, you can get a good product anyways.
3. The flat is finer grained and lacks marbling, the point is highly marbled and coarser in texture. Once you understand that, it is pretty easy to understand what you are eating.
4. Much like pork (and I am no Texan) a chopped brisket sandwich can be a thing of beauty. On a soft white bun, the point and flat, if properly cooked and then given a coarse chop, can be a thing of beauty.
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."