I didn’t initially see the need for this as an established Equalizer APO user, but with crossfeed and loudness compensation confirmed as future features by John on the JDS blog post, I see a lot of value.
It is possible to get crossfeed in EQ APO, but I didn’t care for the results and the interface is unwieldly when you go past the basic PEQ functionality.
It also solves a problem for me of wanting to switch to a portable source when using a work laptop, while also retaining EQ filters (which, with APO, are of coure tied to my desktop PC).