I don't know if it's a waste of time, but I certainly wouldn't stop there. In the same vein, paper tuning is hardly necessary. The only real benefit that I get from it, is to get close when setting my nock height. If you really want to tune your setup to shoot it's best, you have to bareshaft your arrow to tune for spine. Then walkback tune for both centershot and nock height.

I wouldn't dream of paper tuning without the others. As you can see, if you're going to do the others anyway, why bother with the paper tuning. I can usually eyeball my initial settings close enough to eliminate any "getting it close" benefits that paper tuning may give me.