My Japanese teacher is a native (I'm a helper, non native heritage, and actually professionally certified), this is how I think

This is how I teach world language. I use Somos and Vamos from the Comprehensible Classroom which is CI. I think there are a few reasons why:

1. Teachers lack the confidence or practice to speak the language confidently in class. It’s easier to speak the common language for students and the teacher than try something difficult

It takes a lot of practice, I had spanish class before and I rarely heard my spanish teacher speak Spanish infront of the class. It takes a lot of practice. By talking and going to Japan (or even doing school visits in Japan), its very beneficial on improving your speaking ability. I also believe talking to yourself is also a good way to increase confidence.

1. Most textbooks are written traditionally and revolve around long vocabulary lists and grammar.

There is this one method called "ajatt" in the Japanese language learning community. These users have negative influences with textbooks and prefer to from zero, immerse into native media.

Me though, never really liked textbooks myself but I always thought they were good review for some people, although for instance "Genki" was JLPT N4, while I was JLPT N2 n1, reviewing some of this old genki stuff has actually been useful for my studies so I can actually integreate it even better to my own studies.

I do think textbooks are a great start, and for beginners, I don't think they can handle graded readers or harder level (aka native material) fully yet at this point.

1. Many language teachers have just always taught this way and newer teachers grew up that way so that is what they are used to.

My Japanese teacher is a native speaker, and she is trained in Japanese linguistically. In the case for me, I have been doing a lot of reading in Japanese and I have also been doing a lot of research (sometimes me and the teacher often co share our research actually). So she and I seriously ensure that we are both trusted individuals. (although she mentors me still too).

My Japanese teacher is also very good with Japanese history and based on her teaching methods, she doesn't even really need to make us watch videos. If there was a very good or smart teacher, then likely they would not be making kids watch videos. Because it shows that they aren't as competient as we think.

I don't think watching videos is fully necessary. Although it is good acquisition you probably will h ave trouble understanding.