I guess they play into the philosophy of having "no lag" due to keeping the air in the pipe always pressurized?

I suppose the BOV is just ment to improve the life of the compressor section over the LONG term, so when you have unlimited budgets you can just replace the turbo mroe frequently and keep the performance benefit of always keeping the pipe pressurized between shifts.. rather than venting it.

However dosent this slow the compressor down signifigantly during the shift or lift throttle?? or with modern BB stuff the spinup is negligable and the real drawback in "lag" is actually pressurizing the pipe?