Because OpenAI memory can be turned off and is not necessary to use at all?
But the whole point of recall is to store and remember past information. Plus you have a lot more control of what you send to OpenAI with memory enabled, and you can even temporarily disable it. With recall on it's just taking random screenshots and you don't really know what it was all given.
I dunno, it doesn't feel like the same thing at all to me.