Compared to Macs and Windows, it’s a lot better for almost all consumers. I can install things willy nilly on iOS devices with some type of assurance that there are some things that an app can’t do and some things it can’t do without my explicit permission.
Any program that you install on your computer has the same permissions that you have. Time and time again it’s been proving that even so called reputable companies like Facebook, Google, and more recently Zoom (popular video conferencing software that installed a web server on your computer that would automatically reinstall the app after you installed it) can’t be trusted.
And let’s be honest, most of the money on mobile is being made by free to play games where the whales buy loot boxes and gems, or subscription services where you can buy subscriptions outside of the App Store or more recently you must buy subscriptions outside of the App Store or services
I’m not going to go on some strange website and enter my card to download every piece of software and neither are most people. The App Store brings you customers that you would never have.