I have front and rear dresser bars and yes they do protect the tank and my long stock pipes if you lay it over, which I think everybody will do with a 2 wheeled anything sooner or later. DAMHIK
They saved me ton of money for sure. You can also mount some driving lights on them as well as highway pegs.
Someone told me that the big ugly Triumph name badge on the tank protects it from scratching.
The Thunderbird is like a canvas. Some folks go the touring bagger look and others go with the minimalist single seat sort of chopper like bike. Even on the custom look the dresser bars are a good idea just from practicality of keeping expenses low for a drop.
As for highway pegs-I have given up on them when for the second time a big fat bee got scooped up my pants leg and stung me in the thigh. I know he was aiming higher up. I have floorboards and just learned to keep my feet on them at least a big closer to the rear brake.