Most people on wattpad use the app on their phones so big gigantic paragraphs is a huge turn off being they'd get lost trying to scroll which can frustrate them.

It's not a style choice. You don't want frustrated readers because then they'll most likely leave before giving your book a chance.

Example:

Do NOT do this. If you do most of the time people will click off your story upon before even actually reading it. You want readers not viewers.

Example 2:

See isn't that easier to read? Also the better example is taken from my book Call Me Sam so if you plagiarize I'll poke you with a fork. Don't know what plagiarism is? It's a crime punishable by law.