Rover also absorbs marketing costs. They are wildly successful with their tactics, obviously. If you start your own business, you need to consider the costs of marketing, in addition to the upfront cost of having an online presence. Prepare to pay someone to build and maintain a website for you. Not cheap.
You set your own perimeters as to what services you would like to provide, and how much you will charge for each service. My friend probably makes the most off doggie day care. It's less stressful, the dog goes home at the end of the day, but she makes almost as much for that as an overnight stay. More if they are puppies, or special needs dogs.
My point is that I don't see an issue with signing up with Rover. You will be making some money, which is better than no money. To be clear, I still think working at a restaurant or coffee shop is smarter. You will make more money, and have a reliable, steady income.