Conferences where academics present original research tend to charge speakers admittance. "Programming conferences," where speakers are essentially teaching 1-h

Conferences where academics present original research tend to charge speakers admittance. "Programming conferences," where speakers are essentially teaching 1-hour classes, tend to cover the ticket, hotel, and transportation for presenters. Source: I presented research at a few humanities conferences in my previous career and have presented talks at several PHP conferences in my present career.