The new system is much more direct, and should be a bit harder (though not impossible) to fool. That will help ensure drivers keep their hands on the steering wheel when using E-class features like active steering assist, active brake assist and adaptive cruise control.
Mercedes isn't the first to use capacitive steering wheel tech. Cadillac's excellent Super Cruise driver assist uses not only a touch-sensitive steering wheel, but also eye-tracking cameras to ensure that drivers are paying attention. Audi's E-Tron also has a touch-sensitive capacitive steering wheel.
All of this is particularly relevant in the US. The NTSB (National Transportation Safety Board) recently concluded an investigation into a Tesla Model X accident that resulted in the driver's death. It found, in part, that drivers are often over-reliant on self-driving features. It recommended that regulators draw up monitoring systems to "account for foreseeable misuse of automation." To that end, we're likely to see more features like the E-Class capacitive touch steering wheels down the road.