I just read it was funded using a TIF (Tax Increment financing). In the "rebate", the taxes they would have to pay for their development will go directly to the principle of the bond (interest free) they received from the TIF. Furthermore, if a TIF defaults, it's put on the tax payer, and not on the Ark Encounter.
If the source I'm reading is accurate, $62 million was loaned to the Ark Encounter via TIF. Rather than paying property taxes, the taxes go directly to the principle of the loan. If they default, taxpayers pay the tab.
I'm not trying to make a big deal about it, I just wish the public sector had no involvement in this so they can't complain about separation of church/state.
I definitely plan to visit sometime in the next year. It looks and sounds really cool.