We use it in the mornings to order coffee from Seabourn Square and then just go and pick it up (when I say “we” , of course I mean “my husband” while I wait in bed for his return with my coffee ! 😂)
it is useful to connect to the internet, to check dining options (menus) when we are maybe by the pool and haven’t got the paper Herald with us. I have also booked an excursion using the app while on board and it has your itinerary (excursions, spa, TK booking etc).