I think a good self-teacher would be better a teacher than who just hold some fancy degrees. Since good self-teachers always know what students need, and where they failed to grasp the essential, and most importantly how to get them out of obstacles.
And I bet you must be a good self-teacher. I wish I have ever had you as my teacher!
The advantage of holding "fancy degrees" is usually that you have been exposed to a wide variety of viewpoints and insignt that self-taught people might have. People tend to study what they are interested in. Unfortunately, this can produce self-taught academics with horse blinders on.
Imaging you only got your news from Reddit & Huffington Post, saying you were becoming a self-taught news commentator. You'd probably end up incredibly informed... about liberal viewpoints, perhaps not realizing that a large portion of the country doesn't share them. Getting taught in a formal education system (providing the system works) would expose you to a wider variety of views.
There is one glaring fault that a self-taught teacher may have; people learn in different ways. What works for one may not work for all. So the self-taught teacher may not realise that their own personal methods are not necessarily valid for everyone.
And I bet you must be a good self-teacher. I wish I have ever had you as my teacher!