Resorts earn well when there are many guests. The more bookings they have the better. But resorts can actually earn more from auxiliary income if they cater to some of the other needs of their guests. For example, guests who are on vacation love to use the pool to have fun and to relax. If there are kids, their kids would probably need inflatable pool tubes. Others would need goggles. They would perhaps need pool balls to play with.
If these facilities are available, their guests would surely appreciate it. They will not even mind paying a fee to rent them. These are just small fees, of course. But when the resort sums the earnings on these things at the end of the year, it would be a big help in covering some of the overhead expenses.