This particular tool is somewhat unimpressive.

From what's shown in the article it's likely only usable on RedHat-derivatives (because of the binary-only kernel module). There are already "amateur" rootkits out there, with what's almost certainly a better feature set.

I am particularly unimpressed with the documentation's suggestion to rm the module afterwards, as the systems in question are extremely likely to have the shred command installed (which first overwrites the file contents in-place) which would make it impossible for a quick examiner to simply undelete the module for analysis.

I think this was some agent's idea of a PoC more than something they expected to use.