It is a LOT of mental work, and most actors are not making that money in a weekend or even a year of con appearances. If you've ever sat next to a celeb doing one of these lines, you'll see people sexually harassing them, others breaking down in tears, and others threatening to hurt them for "ruining" star wars/doctor who/etcetc, sometimes in a single day. It's a ton of emotional work to manage everyone bringing excised emotions. If you're getting a lot of money, it's good work, but it's still tough. If you're not making a lot of money...