is not necessarily the right thing. It mainly comes from people who put a premium on performance paddling, and it is the style most often taught in the ACA/BCU protocol.
Actually very few people are purely high or low angle. Most of us paddle somewhere in between. I started w. a natural high angle paddle but my hand position was not peaking at my forehead, it was a bit lower.
Learning greenland style I just could not get comfortable w. the extreme low 'knucklebanging' on the deck. So I paddle at a slightly higher angle - but noticeably lower than paddling Euro style.
This is just what's working for me - it's not the best way or the only way.
Correct form can be achieved whatever angle one uses. The more we use the large muscles of the torso the less demand on the arms. A death grip as pointed out is a stress grip. Arm paddling seems natural to a lot of newbies and people often stick w. it as it can give impressive results right away. But is is one of the sure routes to longterm damage for many.
Tendonitis, carpet tunnel, or bursitis (shoulders) is nature's way of telling us to listen to our bodies and make adjustments.