The Web is dying, and mobile devices with dedicated apps are the reason.

That’s what Keith Rabois told an audience at the VentureBeat Mobile Summit last night. Rabois is currently the COO of mobile payments company Square, has been in corporate development at Slide and PayPal, and is a successful angel investor too.

Rabois said that smartphone and tablet users prefer using native apps whenever possible, and only visit the browser as a last resort.

He cited Yelp — he’s on the board of directors — as an example. The company’s mobile apps have one-tenth the number of users as its Web site. But 33% of the actual searches on Yelp originate from its mobile apps. In other words, the Yelp app is a lot more engaging for users.

Square does let customers sign up to use the service from its Web site — Square isn’t ignoring the Web completely — but Rabois said that only a native app gives the “pixel perfection” the company wants as it tries to reinvent mobile payments. As he put it, it’s impossible “to attack anything new on the Web.”

He also defended Color as an example of a company trying to build something completely new for mobile — it’s not trying to reinvent a Web-based social network like Facebook, but is trying to imagine what a social service would look like if it were built for mobile first.

Rabois also predicted that Facebook will soon change its mobile strategy — instead of putting all its focus on building an HTML5 version of its Web site that works on all browsers, it will begin putting way more attention into mobile apps, particularly for the iPad. He said the change would be a defining moment for Mark Zuckerberg — as a founder-CEO, he can admit he was wrong and order a dramatic strategy shift, and his employees are more likely to follow happily.

He also slammed Zuckerberg for saying that the iPad isn’t truly a mobile device. “He’s totally wrong. Once you have the iPad 2, you can’t see any way it isn’t purely a mobile device.” Square currently has mobile food truck customers using iPad 2s as point-of-service terminals.