I use spurs on my boy. Not to refine, because I'm not an advanced enough rider for that, but to reinforce. He responds better to the same pressure on a smaller point than a larger point. I ask first gently with my calf, then firmly, then touch with the spur, and then shove it into his guts if he still won't move. Sounds harsh, but he's had three chances to respond to a "nicer" aid by the time he gets the strong spur aid, so it's HIS choice not mine! He has learned very quickly that it's much more pleasant to respond to a lighter aid... but the moment I don't have spurs on he's straight back to his sluggish, evasive self. He's too smart for his own good. The ONLY way I can get him to move sideways off my leg is with spurs on, otherwise his attitude is "don't wanna, not gonna" and heaven help whoever tries to make him! He's not in pain, his saddle fits, he knows his laterals - he's just lazy, and going sideways is harder than going forwards.
I use spurs in place of a whip, because MY horse can't handle a whip. I would not be surprised if he'd been abused with one, considering what I'm told he used to put up with in his mouth.
Am I wrong? Maybe, but I'd much rather use a firm squeeze with a spur than compromise my position by performing what many call a "pony club" kick - legs out away from the horse's body and boot him as hard as you can in the guts. And yes, that is what it takes some days!
I think, like with any training aid, spurs can be used for many different purposes. Refining the leg aid is just one of these purposes. For as long as there have been spurs, there have been those who use them to reinforce the leg (classically the purpose of the whip) on horses that can't handle a whip, or will deliberately evade one by bulging out on the opposite shoulder, and so two must be used. I'd rather have two spurs than two whips! I might be exaggerating the length of time a little, but I know a large number of people who use their spurs for the same reason I use mine, and to great success.