I don't use Warrior Forum, but from what I've seen, pay forums often tend to offer a higher quality forum experience.
People who pay to use forums tend to be very serious about making money. Forum topics tend to be more fresh and relevant to the industry. Forum owners tend to put more time into forum quality because there's always a drive/incentive to make a profit. If forum quality drops, they lose subscribers/money.
There are obvious exceptions to this.
It sounds like WF is just charging for convenience features. I hope this new business model works for them.