Quantifying impact
Boasting a number like 5 million users not only shows that your game was successful, but also shows that you're used to working on a large scale. It helps us imagine you succeeding here.
Show technical proficiencies
Mentioning specific tools like Unreal Engine and Unity shows us that you're familiar with industry-standard software. It's a little assurance that you know your stuff.
Highlighting leadership skills
Showing that you've led a team before tells us that you can handle responsibility, and that you've got the people skills necessary for leadership. It's a big plus in game design, where collaboration is key.