Couple of points:
- Rimfire was one of the original applications for barrel tuners because with rimfire ammo you did not have the ability to tune the load to the rifle (other than trying a lot of different factory loads). Since you could not really tune the ammo to the rifle by handloading, they basically were tuning the rifle/barrel to the ammo. If you are shooting centerfire, you can obviously tune the load to the rifle, so there is not as much of a need, or benefit, for a tuner. For Rimfire applications, a barrel tuner can make a lot of sense.
- Lightweight barrel profiles was the other original application for barrel tuners. Lighter profile barrels are obviously much more susceptible to whipping, so using a device to limit/control that can be very beneficial. For heavy weight barrel profiles, it is obviously not near as much as an issue.
If you are talking rimfire, or lightweight barrels, then a barrel tuner might be a legitimate game changer. IMHO, outside of those 2 applications, you are heading down a rabbit hole that is really going to lead you no where. Today's high quality heavy profile barrels, with quality handloaded ammo matched to the barrel, are capable of producing very high degrees of accuracy without the need for any type of barrel tuner.