TL:DR, It allows for multi-band compression.
Have you ever set up a compressor so it nicely, gently compresses your G string, only to hit your low E string and have it be compressed to oblivion?
Basically, the Tyler is a High Pass Filter and a Low Pass Filter, with FX loops out of each side. The high pass feeds the Hyper Luminal, only compressing frequencies 550Hz and above. The other feeds the MXR M87, only compressing frequencies 350Hz and below.
By setting it like this, the 12db/Octave roll off of the filters acts as a natural mid cut around 462Hz, which cleans up some mud...just by default of how filters work I guess, but obviously the frequencies are adjustable.
Takes a bit of tinkering to get the settings right, but it works unbelievably well. Hand wired in Germany too, so it's well made!