Why are there both PC and Mac licenses?

[RitsukoSonoda]

How is the mac version distributed? Is it through a 3rd party service like steam or do you have to download it from apple's app store? If its the latter then there is the whole reason for it. Apple tends to be exceptionally greedy as a distributor in regards to the "cut" they take from any transaction done through their billing platform for software or subscriptions for 3rd party services. Apparently Apple had in the past even required 3rd parties to only allow billing for things like in app purchases or subscriptions through apple's billing system which resulted in a case of Epic vs Apple that ended out with Epic paying apple compensation for what they did to bypass having charges for Fortnite things on apple devices go around the apple billing system but at the same time apple being forced to allow 3rd parties to take payment with their own billing systems for software played on apple devices.

It's also a way of sorts to get an idea of market distribution by platform in order to figure out if they should continue providing support for a platform. As an example they didn't remove PS3 support until they were sure most of the playstation players had moved over to PS4 and then did that campaign prior to try and encourage those remaining on PS3 at that time to upgrade and move over.

[VisperCon]

How is the mac version distributed? Is it through a 3rd party service like steam or do you have to download it from apple's app store?

It's through SE. You download the installer just like you would a .exe and launch if that way - same as on PC no additional billing or other requirements as you go through the Mog Station for your subscription.