I thought this was going to be about "fake conferences" in the sense of a real conference, somewhere nice, say Hawaii, and the Doctors are paid to attend, but nudge and wink they just go surfing, and don't attend the conference.

Reading the article, the conference doesn't exist at, and the Doctor gets paid to speak at it anyway, with the "Speaking Fee" explaining away why the money turned up in the Doctor's bank account.

It is a small difference. If you are paying a lot of money for a painting by Hunter Biden, he doesn't actually have to paint it, because you don't really want it, but if he does, it improves the appearance of the transaction.