I also strongly suspect that one of those apps would be WhatsApp, which is an app that a not-insignificant portion of the world uses to communicate. Unfortunately, I don't have a choice in what apps my family around the world uses, so I'm stuck with WhatsApp. The choice for me would either be to cut contact with dozens of family members, or enable the Meta App Store.
My hope is that if Apple is forced to allow 3rd-party app stores, they'll make it possible to even more strictly sandbox apps from those stores somehow.