Front-side illuminated sensors hide the photodiode behind wiring. Back-side illuminated sensors flip the stack so light hits the diode first. Stacked sensors go further and put the logic on a second wafer. The Technology line on a Camemaker page is this family of choices, not a flavour of JPEG.
In one sentence. BSI usually keeps more photons. Stacked usually buys speed or HDR tricks. Neither excuses a 1.0 µm well in a dark room by itself.
What BSI actually buys
Higher quantum efficiency, especially at smaller pixels, and often a better CRA tolerance. That is why phone sensors are BSI. It is also why a BSI 1.12 µm part can still lose to an FSI 2.9 µm part when the lights go down: the bucket is still tiny.
What stacked buys
Room for faster readout, dual conversion gain, on-die RAM, sometimes a small ISP or AI block. The IMX500 story on this blog is one end of that idea. Most industrial parts are quieter about it and still use the extra silicon for HDR and FPS.
How to use the filter
On the sensor library, Technology is a useful second cut after format, shutter, and pixel size. Prefer BSI when the pixel is small or the light is poor. Do not prefer it as a brand. Read QE if it is published. If it is not, BSI is a hint, not a number.