While the premise of the article is accurate, isn't this the part people are concerned about:
> With compiling everything and launching the browser the total time is 51 seconds.
I found similar results to yours. The difference of actually _running_ the tests is quite negligible, but the difference of preparation for running the tests is very large. In our case, 18 seconds (Jest) vs 63 seconds (Karma) from hitting the enter key to when the process is complete. That's pretty significant.