bzip is old and slow.
It was long surpassed by lzma and zstd.
But back in roughly the 00s, it was the best standard for compression, because the competition was DEFLATE/gzip.
Even then, there were better options in the Windows world (RAR/ACE/etc.). Also, bzip2 was considered slow even when it was new.
Also potentially relevant: in the 00s, the performance gap between gzip and bzip2 wasn't quite as wide - gzip has benefited far more from modern CPU optimizations - and slow networks / small disks made a higher compression ratio more valuable.