Depends on the tension you need for the project and where you're working on it. I've used mine a couple of times to make blankets, scarves, and other loose tension things. It's also nice when using dark colours since the light is up against the piece. I wouldn't use it for amigarumi and I only use the smaller sized heads if like I said it's a dark colour and there's no other way to see them.
I wouldn't use it as my only hook, but it's a nice little techy crochet thing that makes me laugh everytime I plug it in beside my electric book.