No it's not. I have operating system wide settings for how scroll bars should work and the rules are complex with visibility and size of the scroll bar changing from one second to the next.
I expect my scroll bar settings to apply to all websites and they are significantly better than what codepen does.
Codepen also doesn't allow me to scroll past the beginning/end of the file, which feels jarring and just wrong with a touch scroll device.
And I'd bet it also falls apart with assistive technology for people who can't physically operate a mouse or trackpad, which in most countries is illegal. Why open yourself up to those issues?