Jamie you are partially correct. In a lot of modern cars the
oil pressure gauge is really an idiot light. The auto manufactures fake the pressure reading by having the needle go to the normal range if there is
oil pressure. This is done to save the OEMs money.
In modern race cars the old style mechanical gauges have been almost completely replaced by electronic gauges. Due to the need to have data acquisition for both post run analysis as well as engine control, most modern race cars are using electronic sensors. Modern electronic sensors have surpassed the old mechanical gauges in accuracy, response, and reliability.
The problem with electronic gauges has been in reading them as well as interpreting them. The first electronic gauges just gave out a numeric number. In a bright light the electronic number could be very difficult to read. The second problem is that the human mind takes time to think and process a number to whether the number is beyond parameters or not. One of the first ways to solve this problem was using electronic bar graphs of varying colors. If the parameter was green then the parameter is OK. If a parameter was approaching a critical point it could be yellow, and if beyond critical it would turn red. I believe the Sikorsky UH-61 helicopter was one of the first aircraft to do this. With this set up a pilot with a quick glance could tell if everything was green he knew everything was OK. The problem with the bar graphs is they use up a lot of dash space.
The other problem with the bar graphs is almost everyone loves the look of the old classic mechanical 270 degree sweep gauges. Typically the old electric gauges were limited to just 90 degrees of sweep. These old gauges were also fairly slow in responding, inaccurate and hard to read. That is why the old race cars ran mechanical gauges. Tachometers really showed the difference in response rates between the electronic and mechanical gauges. Jones Matrola, Smith Chronometric, became the standard for tachometers.
By having the stepper-motor gauge-movement controlled by a microprocessor, Speed Huts gauges can have the easy to read 270 degree sweep, with the response (actually much better) than the old mechanical gauges as well as the classic looks of the old style gauges.
One other consideration is fuel pressure. With a mechanical system, to get an accurate fuel pressure reading, a fuel line needs to be brought into the cockpit.
So for me the answer to your questions is electronic.