Another unnecessary piece of equipment was my second trekking pole, but the extra pole does offer an interesting basis for comparison, allowing you to see what walking 340 miles can do to the foot of a trekking pole.
As for my claim that you can indeed walk through a blister: as you see in the last photo below, my blister from Day 2 of the walk is a shadow of its former self, having healed and hardened despite having been walked on for most of a month.
My Costco trekking poles did what they were meant to do, but if I had this walk to do over again, I'd buy better poles. My major complaint is with my poles' locking system, which uses a flip-and-grip switch instead of a screw-into-place design. The switch acts as a brake or clamp to prevent the pole's nested segments from sliding along each other's length, but if you put your full weight on it, the pole will collapse, no matter how tightly you've fastened the clamp. A screw-into-place design doesn't work that way; it will support your full weight because the only way to loosen the pole's segments is to unscrew them.
Also, my Costco poles' feet reminded me of satanic goat's feet, thanks to their shape. Since I was using only one pole the entire time, I began to think of myself as "half-Sataning my way across the peninsula," on the assumption that the Evil One walks the earth on two hooves.