I have always worn spurs when training, though 95% of the time I don't use them because I have the leg control to achieve that. They are only there for finesse as stated above, or if I know my horse is being a butt and ignoring my leg as opposed to being confused about what I am asking.
It's nice to know that they're there, but if you don't know how to not
use them even when worn, then you shouldn't be using them imo. This is all in regards to spurs other than bumper spurs, by the way. I agree with Iseul that they are a waste of money! Take things slow, allow the horse time to figure it out, be accurate and consistent and you'll get there.