For me, it's not about being good in conversation (neither for me nor for the company's representative). It's about having the chance to ask questions about the true nature of the job, exactly what you will work on, to see if the job really is interesting and a possibly good fit. It's impossible to tell that from job descriptions which often don't give much clue about what your actual job would be like.

If, after talking through it with someone, I still feel like there is a good chance of a mutual fit, then I'm happy to be evaluated quantitatively by my skills. But if a simple conversation reveals that it's not a good fit, then it saves everyone a lot of time since I can avoid the code test for a position I don't want, and the company doesn't waste time evaluating a code test for a candidate who will end up feeling that the role isn't the right fit.

This is just my personal feeling, but for me the idea of doing a code test before ever talking to someone at the company about the nature of the job is like putting your shoes on before you put your socks on.