Aren't Custom Powers just Class Proficiencies and vice versa?

I am not sure I fully understand the distinction between Proficiencies and Custom Powers, or rather the game design idea behind it.

  • In the Core manual the design decision was made to classify what in other editions would be “class features” as Class Proficiencies. For example Magical Music and Arcane Dabbling (Bard) or Divine Blessing and Divine Health (Paladin).

  • In the Player’s Companion something similar happens with Custom Powers: Many of the “class features” of the new classes now appear as Custom Powers.

There’s some idiosyncrasies in the distinction.

  1. What’s the difference between the two? Shouldn’t we dispense with the concept of Custom Powers and just call them Class Proficiencies? Leaving aside the Custom Powers that have a cost that is not one, it would seem that the concepts should be interchangeable. Is there any problem with allowing a character to select a Custom Power as a Class Proficiency?

  2. The system seems to assume or imply that Class Proficiencies are worth more than General Proficiencies. Take Acrobatics for example: It is both a Class Proficiency and a Custom Power of cost 1. But when it comes to learning languages (a General Proficiency), you can either learn one by spending one General Proficiency, or four by spending a class Custom Power. Is this an implicit assumption under the hood, or just a quirk when it comes to learning languages?

  3. When designing a Custom Class, the need to create a list of allowable Class Proficiencies for a Custom Class seems to be internally contradictory: If a DM decides to allow players to design Custom Classes, it would seem natural to also allow a player who picks a standard class to select Class Proficiencies from any class list — subject to DM veto, of course.

Am I missing something basic? Is there anything worth clarifying here? Will this be addressed in 2e?