Presumably, my understanding of Cloudflare is too simple, too rudimentary, or even entirely lacking in some aspects.

As far as I understand it, the main feature is just faster and more reliable access to sites, right?

If I host a website on a server in New York, and someone tries to look at it in Tokyo ... that's a long distance and a lot of potential hops to retrieve the file(s) directly from the NY machine. Cloudflare provides closer-location mirrors of websites so there is less lag time, plus having multiple copies makes my website more readily/reliably available.

That's good, I get that, especially for big, professional business-critical-type sites/services.

But it's not actually essential, is it? Anyone, anywhere on Earth could still visit my NY website w/o the existence of Cloudflare.

Is there more to Cloudflare than this? I realize they are getting into a variety of 2ndary "value-added"-type features, like their own "are you a robot" tests and probably a bunch of other stuff I don't know about ... but fundamentally, are they actually necessary for the Internet?

Why is Cloudflare such a big deal?