It's more like a reminder when you set it up for yourself. If you try to open one of the not allowed apps, you get a pop-up saying it's blocked and asking if you want to open it for 15 minutes or the rest of the day.
If you set it up for a kid in your family, you can set it so they can't get in unless you grant them access. You can also set daily time limits for apps. If you, for instance, want to limit your children's playtime.