I don't think spurs are for everyone or every horse. If you don't know how to use spurs correctly, you can undo some of the hard work you've put into the horse's training or physically harm the horse.
My favorite trainer would not let you wear spurs until she graduated you to them. You had to have a trained quiet leg before she would let you use them.
I've trained both of my horses so the I could use spurs. I've done this because I have arthritis in my knees. As it progresses, I have the option to use spurs or not. At this time, I only use them when I ride my gelding. My mare is so responsive, I don't need to use them at all.
"SUCCESS is not what horse you have . . . but what you do with that horse."