Mobile money grew up as a set of closed systems. Each operator ran its own wallet, and moving value between them was either impossible or expensive enough to feel like it. That design was not an accident — the closed loop was the moat, and it was what made the enormous investment in agent networks worth making.
Interoperability mandates, which central banks across the continent have introduced in various forms, take that moat away.
What changes for the operators
Once a customer can send money from one provider to another as easily as within one, the wallet stops being a reason to stay. Competition moves from network size to price, reliability and what else the provider can offer. That is uncomfortable for an incumbent with the largest agent network and very good news for a challenger with a better product.
What changes for everyone building on top
This is the part with the widest consequences. A fintech company that previously had to integrate separately with every operator, negotiate separately, and reconcile separately can build against a shared rail. The cost of launching a payments-adjacent product falls sharply, and the addressable market becomes everyone with a wallet rather than everyone with a particular operator's wallet.
Most of the interesting consumer financial products of the past few years — savings, lending, insurance sold in very small amounts — depend on being able to collect small payments cheaply from a wide base. Interoperability is what makes that arithmetic work.
The parts that are harder than the announcement
A mandate is not a working system. Settlement timing, dispute resolution, fee caps and who bears the cost of failed transactions all have to be specified, and those details decide whether the rail is genuinely usable or technically available and commercially pointless. The countries where interoperability has changed behaviour are the ones that got the operational rules right, not the ones that announced first.