I've been playing for 49 years and I thank the Lord every day that I played Red River Valley and Home On The Range and learned the fundamentals before I ventured into cross harp and blues.
I taught harmonica for a while too and I always refused to let a beginner jump right into cross harp.
The reason for it is, if you jump right into wanting to be Little Walter, you will fall into a trap I call "Fear of blowing".
Since the foundation of blues harp is draw notes, learning them first bypasses the scales and partial scales that enable you to link things together and work up and down the whole thing.
This will bury you in a rut where you have a (small) handful of draw chords that you will be dependent on and forced to swap back and forth endlessly and it will be MUCH harder to advance into some of the higher level techniques later.
The first 58 seconds Here is a perfect example of what I'm talking about!