It may just be treated like any other commodity and require a CWA, contemporaneous written acknowledgement. Lika a receipt, but with a fancier name. The burden is on the taxpayer to receive that CWA within a certain timeframe before they file, and then the reward for the burden is that they declare it on their itemized deductions like they would any other deducted item.
Does your church have a CPA, accountant, certified auditor, or tax attorney? If so, the church should tell them what type of tithing they want to receive and what type of paperwork the church is obligated to provide to the donator, because you’re paying the professional to tell you how to make it happen. There’s almost always a way. In the overall scheme of paying taxes, #btc is new enough some professionals may just not want to take the liability burden of telling you how to do it.
I think many people would like to donate stocks, commodities and etc to their church because the tax benefit is double. You get the deduction, and you don’t have to create a taxable event beforehand so you don’t have to give up money that you’re planning to give away anyway.