Only last sentence makes sense
Can you finally move out from 90s and arrive in 21st century ? It's no longer a resistor or whatever was used to fool the ECU. Now it's a mini computer with a professionally made map on a rolling road - with a lot more options than remap - you can select from a few different curves - either more power or better economy - AT ANY POINT.
99.99% of daily drivers WON'T need professional remap - and by professional I agree with you - rolling road and fine-tuning - but this makes sense ONLY for people who regularly race on tracks.
I've done 62k+ - NEVER EVER I've had any kind of problems related to my tunning box - in fact no problems at all, just regular servicing - and I really have a lead foot DSG gearbox is silky smooth, no problems with Haldex, on original 8 years old battery and starts instantly
Good quality tunning box is the same as generic remap - but is A LOT safer for the engine. With bad remap, when person doing it doesn't know what he is doing, he can damage the engine by entering wrong data - by accident or on purpose, when disabling safety features. But with tunning box - all safety features are still in place so even if someone makes mistake or data get corrupted - ECU will protect the engine. And if it stops working - you can just unplug it and drive away - good luck with corrupted remap.
And what is the REAL difference in how it works ?
signal from sensor -> ECU reads data from new map and reacts
signal from sensor -> box translates values (based on maps made on a rolling road) -> ECU reads shifted data from original maps and reacts
The only difference is in at what point data from the map is used.
Like I've said - 99.99% of the daily drivers won't even feel the difference in performance - but it would cost them a lot more money.
And with 14 or 30 days money back guarantee - they can just test and return the box.
It is also more convenient in case of write-off or changing the car - box can be removed and used in another car - can even be reprogrammed for a different engine.