I am not sure what the difference is between someone using integrated I pad in dash board with the same interface as a mobile phone to work a phone or using a handheld. Either touch screen interfaces should be banned when driving or not.
If someone uses a hand held device that can also receive phone calls that is attached to the dash on a holder, this is illegal, yet if someone uses the exact same interface that is built in to the dash then its legal.
If someone using their I pad to play to skip song this is legal if they use the same function on the same interface on an I phone to change tune it’s not.
What needs change is legislation to keep up with technology initially hand held phones were considered unsafe as one hand off wheel. Now most phone activity may not relate to calls but using the touch pad for text maps music etc, this is exactly the same if using a built in E pad or the similar my ford touch or whatever bespoke version the manufacture has fitted.
The hand held device problem with diminish more and more newer cars have built in touch screens but the safety problem may not as its taking eyes of road to work a swipe screen that may cause crash. On old cars devices all tactile on new cars can even operate the volume or station without using non tactile touch screen buttons in some cars.
I suppose the problem with the legislation is that it is arbitrary, as comes down is the touch screen built in or not, if not does it the capability to receive calls. So 3 devices with same interface working the same functions 2 legal 1 not.
Would tend to think touch screens should be banned from being used in cars when driving. The trouble is if rules don't come in to force soon on this more of the existing cars on the road with have touch screens, then the normal pragmatic approach by UK gov would just effects new cars then end up with stock of cars that be around for next 15 years with unsafe devices that are legal to use if already fitted.
In Germany as oppose to uk new legislation sometimes effects all cars such as no non cat cars on the autoban even if car is 30 years old and not fitted etc. Apart from the London van and truck euro rules most legislation in uk is on registration date.