Optical sensor is more reliable as most current sensor would drift and be effected by temperature especially next to a very hot turbo.
Optical sensors most definitely not more reliable in that scenario, if it was a sterile enviroment perhaps but not in the conditions required to monitor turbos.
Given the car has target boost/temperature thresholds it's fluctuations should be fairly predictable and be accounted for in the calibration process.
2009 G37 X - Blue Slate - Michelin X-Ice 3/ Michelin AS/3+ Location: The Great White North
Planned Mods: Takeda Stage II Intakes, Borla Catback Exhaust,
G-Stop SS brake lines, Megan Racing Upper Strut-Tower.
“Passion rules reason, for better or for worse.” - Terry Goodkind