A lot of the confusion IMO is encouraged by EA/Maxis themselves - by offering packs that are losing their individual identity..... (by that I mean).....
Offering EPs, and GPs, that both come with new worlds takes away our argument that a pack is an EP because it comes with a new world, and GPs don't. Offering EPs, GPs, and SPs, that all come now with an opportunity of a new career, doesn't help us when trying to argue that a particular pack is rightfully labeled a GP, or an SP because it comes with a new career.
All the packs generally come with BB, and CAS items so that doesn't allow us much wiggle room when it comes to what to call the next pack. We're pretty much at the point here where we are just counting items in the BB build mode to differentiate between one pack to another.
Any arguments we do make we have to attach the words "generally", and "usually" as a disclaimer because there are too many acceptions to the rule. New worlds "generally" come with EPs, and new careers are "usually" in GPs.
Except for the new Kits, the Sims 4 packs are becoming (to an extent) a carbon copy of each other in the sense of offered gameplay options, and features. What is a GP? What is an SP? A description of either can be an explanation of both. The only difference so far that is still somewhat obvious from one pack to another..... is size. The amount of BB/CAS each type of pack has in relation to another.
And I think I even found an argument questioning that as well. So..... what to do with that? lol.