Most perp venues either charge you to post a resting order, or stop at zero.
The rebate exists, but it starts somewhere above your account, be it nine figures of monthly volume, or a share of the exchange's entire maker flow. Below that line, posting an order costs you.
On Grvt, paying makers isn't a campaign, it's built into the fee structure, which is why it applies from the start rather than switching on at some threshold.