I also did better when I turned the tracers off. For me, it forced instinct shooting rather than looking at the tracers. With them off, I was using the reticle rings and canopy frames to lineup shots. I was less likely to do that when I had them on. For me it was automatic, pretty neat.
I recommend trying it to everyone. Give it a few hours to get used to it.
After a few months I turned them back on because I missed the pretty lights, but benefitted from things I learned with them off.