Regatta is a small ship. I’ve sailed on the very similar Sirena. There’s no need for an app onboard. Not enuf stuff going on. No 5,000 pax trying to get their meals scheduled. I can see the need on an X ship, or RCC, Carnival, etc.
In my opinion, no need for an app on O.
Now, “improve the wifi” - did I hear anyone say? YES, now you’ve got me going on that one!