Most important is that the decompression algorithm is stored in each block so that you are able to improve the algorithm without breaking compatibility. Also it allows to always select the best algorithm for the input data and tweak it or even none for random data.
surprised to not find attic/borg in those benchmarks. rar, zip and obnam are not exactly known for being fast backup software...
still, quite interesting project!
It also deduplicates based on a rolling checksum (similar to rsync). Pretty cool archiver.