I like how fast feedback is with this tool, compared to other tools out there! It's free so it doesn't have any downsides for testing javascript applications that are not monetized yet (like me!). You can easily write multiple test cases while developing an application or when working remotely from home without leaving my IDE of choice; Jest / Enzyme etc.. If we need more complex scenarios then yes - additional plugins would be needed but nothing too hard about them either way though :) We've been using wallabys js primarily during development phases where speed matters most because our app has no users at all until its launched which means bugs found early really matter here since they might impact revenue if left unaddressed later down line ;).