Low stretch string does tend to last longer than Dacron, but it will wear from contact with your armguard. Since there are fewer strands, I think it is even more critical to protect it with serving. Speed is over-rated. Quiet is what kills.
I find a great deal LESS hand shock and wear on my joints with skinny D97 strings compared to B50. That, rather than speed, is the reason I use them. The shock comes from the heavy string following the arrow at the shot, then rebounding. The lighter string transfers more energy to the arrow, so less remains to be absorbed by the bow...and you.