WHY?
Unity's OpenURL works just fine. However, it is limited because it works as if you were calling window.open with _self as the windowName parameter. This asset uses window.open under the hood as well but it exposes all of its parameters. This means that you can open links on new tabs/windows using _blank as the windowName parameter, for example, and much more.

ANY REQUIREMENTS?
Your browser needs to support window.open, that's it.