'Das handy', I would expect, would mean 'The handyman', or possibly 'the useful (something)', but I would be interested to know what it really means.

As words come into common and erroneous usage, I've sometimes tried to stem the flow by pointing out the error. A verbally agressive woman once accused me of being a Chauvinist, and when I pointed out that, being of English birth, I couldn't possibly be, and I was not even a Jingoist, she gave me a disgusted look and walked away.
I see that even the modern dictionaries do not classify Chauvinism as rabid French nationalism (as they used to do), nor do they classify Jingoism as the equivalent English nationalism. The two words are now usually synonyms.
Mind you, it worked well for getting rid of her.