Who cares that beat functions fast enough for 90% of the ROM hacking projects out there.
This is not true, ROM hacking cannot stick to NES/SNES hacking forever. Playstation, Playstation 2, Wii, PSP, NDS and many other gaming platforms whose games are more than 300 MB in size need a fast patching tool, regardless of the game size. As I can see, RHDN is a community devoted at very old console hacking like NES/SNES, Genesis etc. but it is slowly moving to 32 bit systems like PSX, as recently opened threads demonstrate. When BPS would become fast enough to produce patches for ISO and NDS cart images, I will definitely drop xdelta.
P.S. By forcing BPS to do checksum verification, many patches obtained from an ISO image would not work in many cases, since ISO images are very dependent on the software you used to make them. This is why the xdelta format is suitable for such tasks, since it can be used to produce checksum-less patches.