I know several people who have met online like this. I'd concur with the authors that working together to achieve an objective is kind of table stakes for an actual relationship. I've always felt that meeting someone in class and working together on homework and what not was something like that. But the key for me is that when you work with someone on a project you get a better understanding of how they approach things and how their values stack up.

Value stacks are something I heard about in a "Marriage and Family" class in college where the professor discussed that if you value say "economy" more than "time", you spend a lot of time to save a few cents, but if you reverse that stack order your spend extra cents to avoid spending the time. If the person you're dating has a very different stack than you do, it will be a source of problems going forward and doesn't suggest you'll have a successful marriage.

Playing video games together should certainly be a way to get a handle on how someone's values stack up relative to yours.