It's just the best general purpose compression algorithm, in terms of compression ratio to CPU used, for the vast majority of use cases

It's just this good.

On a more realistic note: few years back, I've added zstd compression to our log subsystem (hand written direct buffers, native code, in-process, java). For the same CPU utilization if provides twice dense compression compared to regular [-6] gzip (the topic in the title). Zstd is =much= faster on decompression as well, and it this case - unparalleledly better as it uses twice less disk.

zstd is 'silicon valley' (the tv show) - life imitates fiction, except entirely open source