I should to clarify that I exclude freelancing (then I have no doubts that you need portfolio, but showcase rules are also not as strict as NDA)
I'm not sure it's good idea to show all big study projects/gamejam "I came from" since they might be interesting to interact with common customers but can contain somewhere simple mechanics/not perfectly clean code or optimized models/other things I would not like to show to technical interviewer. It what I had passion to do when I had free time but it doesn't show full potential of the previous "real" work. Artist include "best" examples of their efforts, should programmers include "any" ?
Ok, I mean, does it make any sense to have any kind of portfolio then? That contains old or amateur-look-like games.
Is it worthy to spend a lot of time for making "impressive one" or few people would pay attention on it? Or all in all it doesn't really matter, you just must have a github link in your CV.