Video games are designed, first, to waste time. Nothing wrong with that, sometimes you just have time to kill. Second, however, they are designed to encourage routine play. They want you to come back, every day if you can help it. That wasn’t exactly the intention when they were first created, but in effect, it’s how they worked. Now, however, in the day and age of microtransactions, routine play encourages people to engage in microtransactions. You aren’t going to buy v-bucks if you don’t play fortnite on a regular basis, so the developers of fortnite need to ensure their game encourages their players to come back every single day. The more you play, the more likely it is that you will spend money. Therefore, profit.