"You are making a joint by using the strap as a strong, tireless ligament. If you grip tightly, your hands and wrists will needlessly work and stress."
This is how I use trekking poles, to be able to load my arms and take stress off of my legs, while NOT gripping tightly and wearing out my hands/forearms. Let the straps and your triceps take the load, not the little forearm muscles and tendons.
I've never understood how people can get much benefit from no-strap poles. If you load such poles with any signficant weight (which is the main point of using them in the first place), your hand has to apply lots of force to maintain the connection. That's a high price in energy and fatigue in order to save, what, 1 ounce per strap, perhaps less?