No it isn't. Personally, I'm very up to date on what is going on in the world and I've never had a Twitter account and maybe go to the site once a month. Pretty much the only time I even see Twitter is when it's linked in news articles.

It's completely possible to get almost the exact same information you get from Twitter elsewhere. Even in the link you provided, it says that they used Twitter as well as Facebook to broadcast their message.

Twitter is not a utility. It's one of many news aggregators and it's completely possible to live without it.