Flip charts are useful visual aids before, during, and after presentations.
One upon a time the agenda for one of our Toastmasters club meetings almost fell apart. People who had volunteered for roles were out sick, including speakers. Previously I had stepped up as Toastmaster. In the first few minutes of the meeting I wrote the list of roles on a flip chart, and then the few of us present volunteered to fill multiple ones. Our improvised meeting went smoothly, with a long Table Topics section where everyone spoke twice. That flip chart instantly replaced the normal preprinted agenda.
A flip chart can be very effective during a presentation, as was discussed by Ray Anthony and Barbara Boyd on pages 235 to 237 in their 2014 book Innovative Presentations for Dummies. The same advice appears in an article at the Dummies web site. Older but still useful advice from 1992 on How to prepare effective flip charts is in another article at the Educational Research Information Center (ERIC) web site.
And after a presentation a flip chart can be used to record questions.