Inverted venues exist to pull takers in. For a passive trader the calculation flips: you pay to post, but the queue is usually much shorter, so you may fill sooner and avoid waiting behind thousands of shares elsewhere.
Smart routers use inverted venues deliberately — to reduce net cost on aggressive child orders, and to gain queue-position cheaply on the passive side.
Example: an inverted venue pays takers $0.0014 and charges makers $0.0018. Taking 500,000 shares there earns $700 instead of costing $1,500 on a standard venue — a $2,200 difference, provided the liquidity you want is actually available on that book.
Related: maker-taker, rebate, smart-order-router, queue-position