Carl Sagan, like anyone else, can be wrong--but so can you.

In this case, I'm going with Sagan.

To get a simple, qualitative understanding of the most important factor in the process, his "reductive" answer nails it. And he starts going into simple, relevant contrasts, to help students gain a little bit more intuition.

Ida's gravity isn't strong enough. Everest is huge but not huge enough to be crushed by Earth's gravity.

He doesn't say that gravity is the only thing that makes things round. He doesn't say that now you know everything you need to know about roundness. And Mathilde is a little bit bigger than a water droplet.

There's no illusion here; it's actual understanding as can be had with a simple model, with no pretense that the simple model is a complete model.

Seems pretty good to me.