A collection is ultimately just a list of locations, so it can serve any purpose you need it to. You can use collections to plan upcoming vacations, keeping track of all the places you want to visit on your trip; you can also have collections dedicated to intriguing coffee shops, prospective date night spots, or restaurants that have been recommended to you. Every collection can have a name and even custom photo set by you, so you can truly make it your own.
I don’t know how I missed an introduction to this feature with iOS 13, but it sounds fantastic. I can’t wait to try it out. It might be about time to add the beta to my phone too.