It's probably generally true of engineering degrees. While there's obviously an opportunity cost, there's usually not a big out of pocket expense other than living expenses. In my case, it wasn't so much that I really used a lot of specific things I learned getting the Master's but I still think it was a useful supplement to what I learned undergrad--the thesis in particular.

The same applies to some degree of the sciences in general but, there, you probably have to get to a PhD for the opportunities to be significantly elevated relative to a BS.

In any case, this meme about Master's degree scams is mostly directed at high-cost degrees in journalism and the like where the career opportunities aren't great with or without the degree.