How to suggest to our church that they should accept Bitcoin payments?
My best approach would be to show them coinbase.com or xcoins.io or gemini.com and show them how its similar to a bank account. They can log in and check their balance or withdraw to a bank account directly from their wallet.

Tell them that Bitcoin + Coinbase is less costly compared to PayPal: With Coinbase the church can create its own donation button for its website and accept up to $1 million in transactions with no fees (and only 1% after that, compared to PayPal's 2.9% + 30¢/transact. fees). Of course if they accept Bitcoin without any intermediary like Coinbase, there wouldn't even be a 1% fee, either.

Really they're probably not going to know what your talking about unless you visualize it for them. For example in my xcoins.io account it shows my Bitcoin in a dollar amount too so they could see that and not get confused if you know what I mean.