People also post vlogs in kind 1, if that is a problem for you just unfollow? Same is possible with pictures and voice messages or other content.
Discussion
People already post images in kind 1. I don't see the gain in adding a k tag. Just overloads k.
I don't see any harm, either.
for clients that only fetch kind 20 they wouldn’t be able to do the same when its in kind 1, so you need the extra tag to filter our the text messages. I believe Olas already does this
Yes I will unfollow but that would not be necessary if clients would stop overloading kind 1.