I was expecting a comment on sports, but the difference is that most people cannot play sports* because they don't have the fitness to last longer than a few minutes.
*at least those sports who are normally broadcast
It's ok to watch an "expert" like a cook, an artist or an artisan at work.
But when talking about games it's quite different. Games are created to entertain people who play. In the past there have been some crossing into entertaining those who watch, for example chess and poker (mostly watched by other players who wanted to learn to get better), but tabletops, RPG and videogames hadn't crossed that line yet. Maybe some are watching them too to learn to get better, but this is already a bit controversial: getting better to what purpose? If you plan on competing then there's a purpose (even win money). And maybe that could really be the point why it worries me, that people are looking to turn simple genuine fun into yet another competition, as if we didn't already have enough of that. I guess there is still sleep to be non-competitive, so far at least. And the second reason for being disturbing is that it kind of feels like a huge "giving up" when you are spending more time watching someone else doing something fun than doing it yourself.