An additional limitation is that you can only have three such applications installed at a time. You also aren't going to be able to get access to functionality like push notifications (which might be obvious) or network extensions (which might not be: you have to have a paid developer account to develop/install a custom VPN for iOS; I find this limitation particularly frustrating, as it seems to mostly serve the purpose of helping authoritarian governments, and it isn't like Android has such a restriction so we know it isn't "par for the course": they are going above and beyond here).