I have NO idea BUT...

Here's a couple of things I would do if I were in your position and trying to find out.

1. Look at the questions on Quora related to this topic.
2. Look at the questions and topics being discussed in LinkedIn groups.
3. Survey the people you intend to give your talk to before creating the talk.
4. Search for the topic using Twitter search and Facebook search.
5. Go to Amazon, search the words "Crytocurrency" etc. and see what books have recently been released about the topic.
6. Find a really popular website for finance professionals and ask to run a survey to their audience through their mailing list, website etc. re Bitcoin.

Use this survey info to inform your talk.

If I were to pick just one, I'd go with the last one.

Good luck with your talk.

Probably the most interesting aspect in Bitcoin or blockchain for finance folks is the concept of payment channels and how they work and how will that change the perception of cash flow and micro payments.

First, you need to understand which financiers you are applying to: bankers, investment bankers, financial directors of companies, insurers or project financiers?
But one way or another, there will be two main questions: How much will it cost our company and How much money will it bring to us?
Any technology should solve some problem of customers and solve as cheaply as possible. Then it will be in demand and the company will get a significant competitive advantage.
Meanwhile, the Crypto-currencies and everything around them can be compared to the opening of the Old World of America - We know that there is something there, but we can not yet estimate the scale.