in the future there will be a lot less crossover.
What makes you think this will be the case?
I think the answer is to allow either.
I want to be able to use my identity across ssb applications, so this makes sense.
Maybe the solution is to use the same database folder for .ssb, but use a different post type for ferment? This way if we want to build a ferment plugin into 'Bay we can do that and I can use my identity across ssb applications.