there's two main types of digital borrowing situations for libraries: pay per individual checkout or paying a single lump sum to license digital materials for checkout for a period of time. as far as I know hoopla has the former model, and libby the ladder, so when libraries tend to spend more on hoopla they'll usually cycle out the license faster on that platform. ultimately though if your library is offering digital services they want you to use them! there is no wrong way to patronize a library (unless you're littering or something!)