I don't think it's "do things without an audience"; I think it's "don't give the audience absolute authority over your ability to enjoy the thing".

Comedy is good with an audience, and not so much without, so it's a great example.

If you're doing comedy as a hobby, even though comedy is done for an audience, then you can feel free to take time away (or stop entirely) when it's no longer interesting to you. If you're doing it "for the audience" in the sense that the OP is talking about (where the audience is the only point, rather than just being a part of the experience of your enjoyment of doing comedy), then no, the show must go on and you must sacrifice your own interests for the audience's sake.

It's sorta like the difference between the low-key hobbyist mindset of selling something at the local farmer's market vs the high-pressure "obligation to the shareholders" mindset of corporations.

Or to go back to the article title's advice to "stop acting like you're famous": a member of a local improv troupe might doesn't have to spend much of their life worrying about what the paparazzi will say or how the critics or box-office numbers will judge their improv (even though the improv is very directly a performance for an audience), but an A-list celebrity actor does have to keep that awareness in mind at nearly all times, and it often makes their life miserable.