If you're asking in terms of support, Can I Use reports that you'll be fine as long as you don't care about old IE versions. Other than that, I don't see why not. I don't use it very often or see it talked about very often, so I assume most people just don't have much use for it. That doesn't mean you shouldn't give it a try, though.
The only time I think to use currentColor is when I want to make a button with a border color that matches the text color; that's about it. If you can find a good use for it, I'm sure people would love to hear about it.