Under MLAGB and MLAIC rules the use of an over ball lube is mandatory in revolvers. Of course many do not shoot under those auspices but note that all cartridge projectiles are already lubed or have provision for lubrication and this is clearly not there to prevent chain fires.

Some believe that the risk of chain fires is reduced when using BP substitute (MLAGB and MLAIC also mandate BP) but from personal experience I have witnessed a chain fire using Pyrodex - two adjacent cylinders went off as well - he was using wads. No harm done to gun, shooter or trousers once the jam was cleared.

Wads are expensive unless you make your own and the only real use I can see for them in a revolver is as a substitute for filler such as Semolina when on an indoor range - far less messy.