Everything has costs and potential benefits (or harm). Giving a one hour talk to a company of 200 can cost you 30k just in terms of salaries. There is hidden costs in terms of work not being done. And the speaker costs usually large sum.
Is the talk bringing more? Or do you expect it to? Can you just share a video instead of having the talk? Do you expect some return? Or is it just for fun?
Most people never thing about this.