Make no mistake, it is a very strong combo, especially when under Innovation and Waste Not (or Waste Not II). The first 18-CP touch is less CP efficient than Prudent, the 2nd 18-CP touch is somewhat similar, the 3rd is much more CP efficient than Prudent. Overall speaking, if the BSA combo is executed under Innov and WN, it is more CP efficient than Innov + Prudent spam.

However, in manual crafting, especially at endgame, we rarely use WN2 due to its inflexibility. Meanwhile, using WN before the BSA combo has its problems too, e.g. Innov -> WN -> BSA will waste 1 step of Innov, while Innov -> Prudent spam doesn't have this problem. Because of that, the BSA combo isn't particularly efficient with CP comparing to Prudent spam. And if it is executed without WN or WN2, it is not as CP efficient, and depletes durab relatively quickly.