What Stuart82 said. Plus, there's an old saying that the championship doesn't make the superstar, the superstar makes the championship. Back then, there was only one world title and the Intercontinental Championship still carried around a lot of prestige and meaning as the second major championship of the company. Why not then put it on the most popular star in the company? It wasn't time for Austin to win the Royal Rumble and begin his main event push yet, so putting him into the Intercontinental Title picture for 4-5 months was a good booking choice. Also keep in mind that the original plans called for Bret keeping the WWF Title until Wrestlemania 14 where he would then drop the belt to Austin and put him over with a pinfall loss for the first time. So feuding with Owen was a good way for Stone Cold to continue his feud with the Hart Foundation in the Summer of 1997 without over saturating his feud with Bret specifically by just wrestling him and only him over and over again.
You can say that guys like Hogan, Undertaker and Yoko never won the IC Title before winning the world title but a lot of guys did. Ultimate Warrior went into his match with Hulk Hogan while carrying the IC strap. He forfeited it only after defeating Hogan for the world title. Bret lost the IC Title only less than two months before winning his first world championship. Shawn Michaels won the strap one last time in the Summer of '95, even though they must have known already that he was getting the world title push come the next year's Rumble and Wrestlemania, which he did. The Rock, like Austin, was IC Champion for the final time only three months before winning the WWF Title. John Cena won the US Title (which was the second most important championship on the Smackdown brand then) before winning the WWE Championship, and in fact, held the title even during the build to his match with JBL at Wrestlemania 21. He only lost the US Title like 3-4 weeks before winning the big one.