I know that they don't work exactly the same. A POV is more or less a safety device that releases the pressure whn you wstegate malfunctions so it doesn't ruin your motor. A BOV releases the exsess pressure that you rturbo creates after the throttle plate slaps shut, which could cause compressor stall giving you turbo lag.
a BOV and a POV aren't the same thing, but the way assclown made his comment gives no real information and was blatantly annoying...
you're right. from my understanding a POV just vents excessive pressure as a safety fallback device.
and I believe a BOV helps limit compressor stall by venting pressure from behind the compressor turbine when the throttle body closes. Otherwise the air would hit a wall (the closed throttle body) and the turbine would stop, causing turbo lag but also causing the exhaust turbine to stop spinning which causes excessive back pressure and is bad for the turbine... but Zbum or 88hybrid would be more qualified to answer that than I am.