I hate that logic, it is flawed to the very core.
BMW has expensive engineers. They spend billions in R & D. Somewhere, sometime, under a specific set of circumstances you and I may never know, it became evident that those canisters were needed. They had a 6 digit engineer design, test, and design mounts for the canisters. Then they paid a programmer to program a machine to cash them. Then they paid for the machine to do so. Then they produced them on every single N54 ever made.
Sound cheap to you? Let's say those parts cost $1.26 per car, everything accounted for. I'm going to estimate 5 million produced, which is probably a quarter of actual. If BMW could save $1.26 per car by eliminating the vacuum canisters, they would save 6.3 million dollars. I'd say that's probably worth it.
BMW does not add components for fun. In fact they have hundreds of engineers employed whose only job is to eliminate unnecessary components. This is the entire reason for the N55, save component cost.
