"Interesting that" is just a figure of speech that people use to introduce information weakly related to OP.

Haha right but it’s interesting that Charles Darwin was the grandson. It isn’t interesting that they didn’t mention it. Sorry for perpetuating meta discussion.

I'd argue that it is an interesting element to the story. To add a little hyperbole, the wealth cascaded down two generations and helped enable a lifetime of serious scientific work that fundamentally changed the world.

Fair enough. Consider me convinced.