The main benefit of casting is not building an audience (though that can be useful, too).

It's error correction.

By exposing your work and your thoughts to the public, you are getting them criticized, and any lurking mistakes are corrected more quickly.

Co-Founder at sablier.com, and open-source developer. I have a broad range of interests, including longevity, epistemology, physics, and psychology.

I totally agree with you casting's real value lies in error correction or review through public scrutiny. You get to refine your ideas, identify blind spots, and gain new insights.
It always works in both ways personally I like to see your cast because I know I am about to gain something