It depends on what you mean by 'featured'. Are you hoping to become one of their paid WEBTOON Original series? If so, then no; the majority of the WEBTOON audience is on mobile, and the editors are quite firm about vertical being the format of the site.
If you mean 'featured' in the sense of getting on one of their 'recommended' lists for a few days, you have a slightly better chance, but there's still an overwhelming preference for vertical comics.
I did have my comic featured on Tapas for a week while it was still in page format, so it seems more possible here!