I didnt notice anything significant as far as wear on the mains. Normal weaves displace the strings repeatedly anyhow so not too worried
Also i am using kevlar mains so probably wouldnt notice anyhow. An fwiw i abuse the mains while stringing anyhow. I will “walk tension” from inside to outside and deflect the mains alot while under tension. This tool was a walk in the park for the mains compared to what i do.
Also it seems like you are forgetting the reduction in interstring friction while pulling tension on the crosses has to result in less wear overall vs normal methods
Due to your extreme methods, you’d be an interesting case study.
As a hypothesis, what might we expect? Deflecting the mains with the tool - which are tied off at this point, so it’s not quite the same as what you do whilst stringing - you might not be surprised by a decrease in tension. Less friction when pulling the crosses might result in an increase in tension. If this were true - only a hypothesis - then it may be that different tensions are required than you would use stringing without the tool to compensate for lower force on the mains, and greater on the crosses.
I’m not forgetting the friction when pulling crosses, though if conducted with the widely accepted method of fanning the strings, would argue that any wear is so minimal as to be insignificant. Anyone who can visibly see string burn is doing something wrong!
In general, I don’t object to this sort of tool. I can see how it has a place for those who rarely string, and are unlikely to develop particularly proficient weaving skills due to that. And that’s no bad thing, and not meant to be detrimental to those stringers - much like on court, there will be those who are complete beginners, the touring pros, and everything in between. What I do notice though are claims from manufacturers that it’s in some way ‘better’ or ‘gentler’ on the strings, with nothing to back it up.