Ok...getting back on topic....
Relaxers use harsher chemicals than Keratin treatments. Plus, Keratin lasts for about 5 months or so which avoids women getting bored of having the same looking hair for too long. There are some really safe Keratin treatments that use natural oils like argan oil to significantly reduce damage. I've used Cocoa Keratin Smoothing Treatment and there has been no damage whatsoever (it has argan oil in it!).