1 There are not so many average users on this forumDefault allow is much better suited to the average user.
2 A skilled friend or family member can set up a default/deny system for the average user in a way that will work for them.
3 The problem is mainly with average users who like to install new programs and have a lot of software. There is another kind of average user: the one who doesn't even know how to install programs. For them, using a default/deny system is as easy as can be.