Whatever we think of it, you have to admit that it's quite "genius".
The door to door ministry as done in western developed countries where the JW quirky religion has probably reached their saturation level was a complete and utter waste of time in terms of the effort expended to recruit people.
At the same time, it was rarely something that anyone enjoyed which led to people being labelled as inactive, being pressured to doing more and maybe ultimately deciding JWism wasn't for them and leaving.
There was also the issue that many JWs are actually pretty bad at knowing and articulating their beliefs so were pretty incapable of getting any meaningful message across.
They solved all this with the cart witnessing. The real point isn't to recruit, it's to make life easier for JWs. Now they can stand and chat with their friend, have a coffee, not talk to anyone or make eye contact and still act as a walking billboard for JW.org. Witnessing becomes easier, more people can keep the definition of "active publisher" without so much effort and it probably doesn't put a dent in the recruitment numbers at all and the organization has complete control over the message so JWs don't need to know what they believe.
You have to hand it to the WTS, that's pretty smart thinking.