Definitely not. In the general case, you will make things simpler and faster by turning reflection-based code into generic code. What this article says is that

Definitely not. In the general case, you will make things simpler and faster by turning reflection-based code into generic code. What this article says is that a function that is generic on an interface introduces a tiny bit of reflection (as little as is necessary to figure out if a type conforms to an interface and get an itab out of it), and that tiny bit of reflection is quite expensive. This means two things. One, if you're not in a position where you're worried about what does or does not get devirtualized and inlined, this isn't a problem for you. If you're using reflection at all, this definitely doesn't apply to you. Two, reflection is crazy expensive, and the whole point of the article is that the introduction of that tiny bit of reflection can make function calls literally twice as slow. If you are in a position where you care about the performance of function calls, you're never really going to improve upon the situation by piling on even more reflection.