Absolutely useless skill, in my humble opinion - prioritizing style over substance. Most people's attempts at cursive produce an illegible scrawl (as any recipient of a doctor's prescription can testify), and even good cursive can be difficult to read quickly. An ability to write plain, block text clearly is all that's needed. I'd be concerned if my kids were spending time learning cursive when they could be learning math.
Another useless lesson is Roman Numerals..............
But I can type faster than I can write anyway, and I take my class notes on my lappy, so...
Unfortunately, most of my students cannot even manage that.