I don't get the point of it either. Most who want instant transfers already have Revolut and won't download a second app. Also, where a group wants to share a bill it's likely that one or two members will only have Revolut and no Irish bank account, thus rendering the indigenous payments app pretty useless.
the reason they are doing this is because their legacy systems are in such a state, the only way to compete is to build something new like this. I wouldnt be surprised if they got and build their own new fintech bank, they should. The amount of systems that dont speak to each other in real time in the legacy banks would amaze you.
I still think this is complete madness - if they think they are building a barrier to entry, then they are too late, with Revolut, Bunq and N26 already in the market.
SEPA Instant already does a great job, facilitating cross border transfers, available to both business and personal customers etc.