The main question is: What about push notifications? WHAT ABOUT PUSH NOTIFICATIONS?!! Even if we sideload an app, with modern mobile OS architecture many classes of apps will be almost useless if sideloaded apps will not be able to use push notifications provided by an operating system.
No, too many apps wants to interrupt whatever I am doing to nag/inform me about non time critical stuff. I have disallowed notifications for almost all apps on my iPhone. I will check an app when I want to check it, not when the app developer wants me to.
Do you want WhatsApp to deliver a message to you from your mom or special one that they urgently need help? Or should they wait till you will want to check the app?