You initial thoughts are dead on....however, poles are a personal thing. Pack weight and over all stuff weight at their minimums.

I own both telescoping and fixed length trekking poles. Since I maintain a nature preserve, my fixed poles get used 99.9% of the time.

My fixed poles are re-tasked ski poles and I find them both lighter and MUCH stronger than telescoping. They will not collapse on steep downhills!

My reasons for poling are:
1) I tend to roll my ankles. Since I started using poles, maybe 15 years ago, I've not rolled an ankle since!
2) Poles make great tools! I've caught/relocated snakes. I've whacked vine tangles and cleared spider webs off trails! Flipped rocks and branches off trails. Poles are great for bushwacking and moving brush out of the way.
3) They add a nice purchase for general steep climbing, no bending, much less tired. Might as well use those arms!
4) My tarp would fall down without them...poles serve more than one purpose.
5) I tend to hike faster, less fatigue, even with just one stick!

I would highly encourage anyone interested to buy up any old ski poles you find at garage sales or wherever. Knock off the baskets. Usually the grips and straps are already perfect, but modifications are very simple. Ski poles don't rattle, don't collapse, have no moving parts, and once you learn how to use trekking poles, you won't be adjusting them anyway.
paul, texas KD5IVP