That was my first question when the Ineos rep told me about the missing dipstick.
According to him, this is not the case with the B58. The only requirements are that the oil has not less than 60 °C and the car is level. And that makes sense imho: The time needed for the oil being collected in the oil sump is a known value, so the 'real' amount of oil can be calculated. I know this guy already from the Abentuer & Allrad fair, and to date, he's always been conscientious with his answers.
Though I find it a bit crazy that to check the oil you
first have to start your engine (to get it hot) and
then get the result ...
Apart from that, my personal opinion is that there should be a dipstick in any motor. A sensor can fail, a dipstick not. And there are no piston-engines without a dipstick in airplanes - for a reason.
Before every flight, we even measure the fuel level with a wooden stick, although we have fuel gauges in the cockpit. No joke.