I've tried that in most countries I've been to. The results have been hit-and-miss.

Japan: Works great Turkey: Nope. Thailand: Nope. France: Works, but not always well

In a lot of countries, cab drivers are illiterate. And I don't mean functionally illiterate. I mean simply CAN NOT read. Not even a map. If you don't speak the language absolutely fluently, you're screwed.

I could, but sometimes addresses are not so clear. In my experience taxi drivers like it when you can explain directions and negotiate price. Without common language for me that is quite difficult.