It's a checks and balancing system. Laser and level will give you perfect center shot and a level arrow. Sometimes that's all that is needed IF the shooter has good form, there are no other bow issues etc.

My Allegiance, that's all I did was level and laser tune it, no paper, etc and it shoots perfect darts and has all broadheads I put through it hitting with fieldpoints.

BUT, I got lucky. Paper will show you inconsistancies in a shooters form such as torque, arrow spine issues for just some examples.

Again, all the tuning methods will fix most issues. Some are not always needed.