I think the basics of it (i.e. recognizing n vs n^2 vs exponential) is important for back end developers. After a few years of doing back end I've definitely had to have awareness in how I design things like my loops to optimize.
It's not a biggie for most companies, but you should have a general awareness. Unlike the author of the article, though, I do believe you can learn this on the job. Also, you don't have to necessarily know the big 0 notation, it's a good idea to write a load test which will give you a more relevant stat anyways. But sometimes its good to recognize "Oh I don't need a 2nd inner loop that will change this to O(n^2)".
It's not a biggie for most companies, but you should have a general awareness. Unlike the author of the article, though, I do believe you can learn this on the job. Also, you don't have to necessarily know the big 0 notation, it's a good idea to write a load test which will give you a more relevant stat anyways. But sometimes its good to recognize "Oh I don't need a 2nd inner loop that will change this to O(n^2)".