Evergreen vs traditional fund?

Trying to understand high level the main differences / reasoning an investor would choose an evergreen fund vs a traditional fund commitment. Also, what the reasoning is to create an evergreen fund vs a traditional open-ended vehicle. Seems like a traditional fund is IRR-based whereas an evergreen fund places more emphasis on the total annual return, so in reality you should be comparing the two between their MOIC? Any and all insight much appreciated!