Convenience.
If you're running a linear phase EQ plugin like EQulibrium you still need a host program, so you have that annoyance. Additionally, linear phase consumes system resources and you have latency, so lip sync in games and movies can be an issue. Then there's SonarWorks, which has the ability to run in Linear Phase or minimum latency mode, which is nice. However, if you want to change your EQ a lot, it's irritating to have to go back into the app to switch it on or off, or modify the EQ curve. With Loki, the physical device is always right there. You flip a switch to engage or disengage EQ, and you can mess with the four bands whenever you want, no matter what you're doing on the computer, and the quality is always good.