And nested ), ), and ) are easier to pick apart visually?
At least with }, ], and ) you know any given } matches a { and not a ( or a [. Whereas with all )'s, it's a lot harder (for me) to know which ( in a mountain of ('s it's going to match.
A good editor and proper indenting will, of course, mitigate some of the pain. But I'd MUCH rather have a mix of {'s, ['s, and ('s, than all ('s.