> not having to chase down dangling missed closed brackets or rely on an external tool to highlight 15 levels of parens and/or auto insert 10 ugly parens at the

> not having to chase down dangling missed closed brackets or rely on an external tool to highlight 15 levels of parens and/or auto insert 10 ugly parens at thee end of a nested code block is a nice QOL improvement in my opinion. Development environments with syntax support are common. These are not "external", they are nowadays "integrated". See the features of typical Java IDEs. Java uses tools to edit code, so does Lisp.