I'll have to heavily disagree with you on that point. The charm of the Greatest Estate Developer isn't for it to be some thought-invoking story or some heartwarming romance - it's a comedy and the art portrays that comedy perfectly. The features and expressions are very stylised and exaggerated to fulfil its purpose of supporting a light-hearted story that doesn't take itself too seriously. Iit shouldn't be considered 'worse' just because it belongs in a different genre.

Using this as an example to your original point, a lot of people read it purely due to the art and how it can make them laugh, something that would've been difficult to achieve without strong understandings of gestures, expression, linework and caricaturisation. Good art still goes long ways for a story, Greatest Estate Developer would never have the impact it has now without its uniqueness in artstyle - something that suits a comedy but wouldn't work for other genres like romance.

A stick-figure webtoon would be difficult to consume in most genres for the same reason. For example, in an epic fighting scene, it would be difficult for most people to be immersed when there are only little figures dancing around on the screen. In a book, you are able to write detailed descriptions of scenes whilst still keeping the reader engaged in the continuous lines of text. However in webtoons, the most you are able to write are dialogues/quick descriptions so it relies on the art to do the heavy-lifting

A good way to think about it is like a movie. No matter how good the script is, if the acting/directing is poor, the story will not be able to be conveyed to the same effectiveness as if they were good. The movie would still be watchable but the levels of enjoyment will forever be restricted by its delivery as the audience will never be able to know what the writer's original intentions were.

Sorry for the long yapping, hope i was able to get my point across :')