Why it would work:
The thought is that as engine rpm's increase toward redline boost pressure increases also. As this happens the bypass valve opens up a small amount to prevent the supercharger from producing more than a specific amount of pressure.
By controlling the action of the bypass valve it's thought that boost pressure would increase and generate more power.
The concept with a boost controller is that it measures boost pressure and regulates the vac source to the (in this case) bypass valve controlling its position. Some are as simple as a Granger valve or as complex as a microcontrolled relay valve that pulses open and close many times a second to limit the vac source to the bypass valve.
Why it wouldn't work:
The thought is that more air is needed to produce more pressure and by closing the bypass valve the s/c will suck more air through the MAF. The CFM limit of the MAF in relation to the PCM is unknown and it may set an SES light or even induce a limiter. Additionally there are more than one MAP sensor that also could trigger a limiter or SES light leading to at best more power and worst engine failure and BCM recording of the whole event. Also there is an electronic controlled throttle that may play a part in limiting the volume of air entering the engine and that brings on a whole new series of issues to the table.
A little time with a recordable scanner/voltmeter and it would be 100% possible to answer this question one way or another.