No, it’s a function – the return value is what is displayed in the quote box.
As for the issues regarding clutter of multiple layers of nested quotes – it was never really a problem back when it was the default. Just like most people are savvy enough to edit down a quote to only reply to the relevant part, I think most people are savvy enough to cut out unnecessary layers of quoting.
The reason I like the feature is that since the default was changed to no nested quotes, you end up with people commenting on other people’s arguments without context, e.g.
What statement is poster A disagreeing with? Now I have to scroll all the way back up, giving myself crippling carpal tunnel syndrome.