It's an effort barrier. Similar to the logic behind 'if your checkout process is x% faster you'll convert y% more customers'.
I didn't think about it at the time, but post analysing: I was mildly interested. Was going to try a game, but registration is a (small) faff so wasn't worth the effort.
I didn't think about it at the time, but post analysing: I was mildly interested. Was going to try a game, but registration is a (small) faff so wasn't worth the effort.