You're right, but I do appreciate getting GTA V for $0. They'll never get a cent from me but I'll take their games. I'm also running Windows so nothing about my gaming is free-as-in-air anyways
Chances are they have already gotten more than a cent from you -- depending on what they do with your account data. Even just an email address has a price. That's my only point, really. Just signing up gives them something.
But it wasn't worthless to Epic, who potentially sold it, active address or not. It doesn't really matter what happens with it further down the chain after that sale. The point is that simply signing up for an account, even with fake credentials, does give Epic something. Not a lot, but something.