It’s a nice tool to have. As other have pointed out, it’s doesn’t do anything you couldn’t do with a bubble level and a tape measure, but it’s still pretty convenient. For instance, mounting the second stand at the same height as the first was completely trivial and saved me a bunch of time measuring stuff.

My recommendation would be to look at a set with a bunch of accessories to adjust the position of the level, otherwise you’re gonna have a hard time playing it at the correct height, especially when using the horizontal lines.