That's about what I was thinking, although I expect that Wave will try to cull a variable income on the value of transactions somehow, rather than merely deriving a seat-volume-based TAN licensing revenue stream. Perhaps they aim to achieve that from the enterprise side of the transactional equation. Which may mean there's another server-side enterprise product on the way.
It's an experimental thought at this stage. A more optimistic one than any I've seen here regarding the MNOs (as there seemed to be a consensus they were in the way and that Wave needs assistance from third parties to sweep them aside). But it is not more likely for being optimistic.