They're different products, Wero offers features Bizum does not. Ultimately Wero is a product banks can make more money off of so they're likely to invest eventually. But atm Wero is unproven in the actual market, so it remains to be seen how well it will catch on. That's why these banks don't want to make the switch immediately, and prefer this expansion route first. If the consumer demand is there, the banks will follow.