The long answer? Definitely yes. Primer allows colored eyeshadows to really pop without having to layer on (read: waste) tons of product. It usually goes on smoother and stays on better as a result. End result? Totally worth it.
If you want you insanely too bright, covers way too much to be reasonable, really red eye shadow to stay bright over an extended photo shoot then you definitely need primer. (I’m allowed to say this is crazy, it’s my own work.)
Primer prevents darkness under eyes or on eyelids from interfering with the pigment of the eye shadow. This can be enough of a benefit on it’s own, but it gets better. Some companies are starting to work on eye shadow primers with ingredients that work like eye creams and actually make your skin healthier. Fantastic! Minimizes my routine and I love it.