You can load any app you want, but it disappears after 3 days. Then you have to load it again. To keep the app on your phone, you need to load it onto your phone again every 3 days using your computer.
It's obviously set up for developer testing, not for someone trying to actually get use out of an app on their phone.
Edit: Ok, "true depending". If you are a registered developer then your apps last a year. If you are unregistered then you get one week, which would be a total pain in the ass.
I don't understand what risk they are mitigating by keeping the unverified developers to 3 days instead of one year. It is clearly an intentional action.
I guess you could have a business where you install unapprovable apps for people with a 1 year subscription and they have to physically come back to your kiosk and get an update from you each year.
I've heard that there's somewhat of a black market for this already. One person buys a developer subscription, then signs apps for other people so that they can sideload them using something like AltStore. Then, Apple sees that many apps have been signed by one dev account and shutters the account for terms of service violations. Finally, someone else registers a new developer account and the process repeats.