from what I've seen, manhua get printed in books with a similar format to manga - i.e. no gaps between panels, and content fitting inside the panels rather than loosely floating around them. So it seems that the long scrolling manhua is really only for mobile/thin device viewing only - it's specifically for that medium. Which makes sense, I've tried to read manga on my tiny phone screen and it's not easy, you have to keep zooming in all the time to read the text, and a lot of the details are too small to appreciate. So in addition to aesthetic preferences, it does depend on how you're viewing it as to what is best I think.
I'd be curious to see how easily the two formats can be converted from one to the other. As a manga artist, how easy is it to spread your panels out and make them into a manhua, and visa versa. That way you can cater to a larger target audience by formatting your work to suit them. I get the feeling a fair amount of redrawing would occur both ways, but probably no more than 20-30% of the original creation time.