It's worth it if you're in the 1% of titles that succeed because of Steam.
The next question is should any company have that kind of power.
Steam's monopoly is a real problem. Microsoft had less of a monopoly on computers when they got investigated.
That's not true at all. Steam does a lot more than just list a title...and there is a ton of shit games that are put out there, they don't make it because they're shit, not because they're not part of some magical 1%. Tons and tons of indie games have made it because of steam. They akso don't have a monopoly, its just what most people use. There is still the epic market, itch.io, gog, humble, etc all of which you can choose to sell on or not.
It's a de facto monopoly, just like windows was a de facto monopoly despite macos and Linux existing.
There are plenty of good games that don't make it on Steam, and Valve does very little for the money.