I'm a JS learner so I'm not sure if I can explain with authority why it's good or bad, but I can tell you based on what I've seen in other codebases:
Sometimes referring to this is inevitable, and in those cases it always makes sense.
Sometimes using this can add clarity to what you're writing, so I've seen it be used rarely and carefully and it was a bonus to legibility.
However, some people have really weird beliefs about this and use it all over the place, and have convoluted ways that they bind() and pass this around. If you see this everywhere, or things like var this = that and stuff, to me it's a code smell and it says that the developer, though they have found a way to work, probably doesn't really get how JS works.
I wish I knew more about it so I could explain what I mean better, but I'm hoping a JS developer can elaborate on the things I've seen :D