There is a huge difference between going the Pay Per Click Route and Earning your ranking.
Earning your rankings in the search engines means content. It means that the content you are posting are worthy of ranking well. Let’s assume that you sell “green widgets” and you publish a page saying “we sell green widgets”. That might work in some limited cases, however the better route would be to say that you sell “green widgets” and then further include on why your “green widgets” are better than anywhere else that your prices are better and your customer service is superior.
Some ask why does that matter? Well the reason is because some people might search for “best green widgets” and if you took the first route you would not come up for that term. Another reason is that honestly people do read the content on your site. You need to convince them that your product is better.
In other words lengthy articles have more keywords that match the search queries and make for a better experience for the end user.
This allows for a far more varied keyword set than what would be possible with short articles. Another thing is that when one starts writing longer articles, then tend to include more topics and more ideas that what would be possible with a short article.
Another thing to state is who shares tiny articles on social media? Most likely the other major source of traffic would be social media, and people tend not to share small articles because it’s much easier to just cut and paste that paragraph rather than cut and paste an entire article, typically entire articles deserve a link.
Now buying a ranking, literally just pay per click is viable for short content. But the moment you are done paying Google is the moment the traffic is gone. Whereas the lengthy article you published and ranks well and has been shared on social media will remain there for years.