The screwdriver bits are available in special "security" bit sets. These sets however, only contain very short bits, so you do need a specific screwdriver of the particular size with a suitable narrow shaft. A piece of coat hanger wire and a file will sort it out for you. (A vice to hold the piece while you file it will be particularly useful.)
They arguably use the security screws to prevent people pulling it apart and fiddling with it, then complaining and expecting warranty when it fails.
For mains appliances, it is similar but with an added safety concern. There is also an element with more expensive devices, of restricting service to firms who pay (through the nose) for service documentation.
Not sure what they use to synchronise the display, but it may be the same light sensors used to detect the pen, measuring the ambient illumination over a full rotation.