Yes, I read the article - it caches my pages on Cloudflare’s “edge” servers.
But isn’t that what Cloudflare is already doing for me?
Welcome to the Cloudflare Community. 
I’m not sure which article you read, but the point of the Cloudflare WordPress plugin is to provide convenient access to some of your Cloudflare settings from within your WordPress site dashboard.
You can use it to purge your cache after making changes to your site author having to sign in to your Cloudflare dashboard. The easiest way see what you can do with it is to install it and connect it to the corresponding Cloudflare account. Note that some features are only available with an APO subscription (which is included in paid plans).
That’s it? Just to save me going to their website?
That’s one of the benefits that I find most useful. While not my use case, the plugin would allow a collaborator who does not have access to the Cloudflare account to perform certain tasks.
As I mentioned, there are additional features when used in conjunction with APO. It is strongly recommended to have the plugin installed if you use APO. More information is listed on the official plugin page.
Do you have something specific that you are trying to work out?
Meh - tried it — turned on that APO and it just screwed up our site – a bunch of icons no longer displayed in our store.
Turned it off again and then had to go back into main website to purge everything.
So, no plugin for me.
I use Fake (a website automator) that can automatically log into a website and even click buttons and I don’t even have to run a browser. I’ll stick with that!