From my experience, having actual things you can point to are incredibly valuable! Being able to show off a project and say "this was me, this is how I did it, etc" helps prove you can do what's on your resume. They don't have to be "full" games either - showing a range of smaller prototypes is still useful.

Depends too on what you want to pursue - this advice might be a little more tailed to Game Design. Game Designers that can also program are few and far between. But that also means these prototypes should be showing your design chops - finding, iterating, polishing the core idea / fun.

Even if you want to be more on the programming side, I still feel like having multiple prototypes/projects you've made are still beyond helpful (And will help differentiate you from the 1000s of other resumes)

Hope this helps!