This is a pretty personal choice based on what you intend to do with the app and the audience. If you think there’s a big enough audience it’s likely worth making it a public app to make it easier for others to find and install. It will have some approval steps the other 2 types don’t have so maybe that might impact your decision making. Whether you want to use the billing api or not will help force you in a certain direction. If it’s more likely to be a one off and the build will be done as a billed project you might go for the single merchant install link.