Could be smart to really push the fact that credit/debit cards were never meant for use on the internet. Internet didn't even exist when cards were first envisioned and created, whereas Bitcoin is built from the ground up to handle payments over the internet.
Also, in order to accept payments by cards, merchants need to register+pay fees+++. To accept payments in bitcoin, all you need is a private key (i.e. a number with some specific properties).
This. This. This and This.
Know your audience. Those in the audience won't care about ending the Fed, the conspiracy of monetary inflation, the abuse of banks, anything about fractional reserve, or the benefits of anarchy and the power of Bitcoin to defund the state.
Know your audience. Anyone who has accepted credit cards only and lost money to either identify fraud or so called "friendly fraud" will care about how CC & Internet don't work well together. IIRC something like 90% of all credit card fraud involves "card not present" transactions. It was never designed for that any everything in the past twenty years to reduce/control it has been a bandaid at best.
Painting a picture for the audience about how Bitcoin is better for the merchant
1) no chargebacks --- ever
2) no need for a processors however processors (bitpay) can exist because many merchants want a turnkey solution
3) low/negigible fees (don't say "free")
4) open network, anyone can participate, build value added services, etc.
5) merchants can eliminate the cost and expensive of trying to identify their customers to stop payment fraud.
6) merchants can accepted orders from Somolia with no more risk than New York (use name of city where conference is located).
7) merchants don't need to hold on to cardholder information and thus there is less liability to the merchant (identity theft lawsuit) in the event of a breach of the merchant's servers.