A large fraction, perhaps even most, trips are in the company of someone else. Often said someone does not have a bike. As a result, the combination is the slowest of both worlds - the bike has to be unlocked and locked at the ends of the trip and the distance is travelled at walking speed.
Note that the unlock/lock time exceeds the time saving from extra speed on short trips.
If you're more than 2-3x faster than pedestrians, you're a danger unless you're separated from them, and bicyclists are rarely separated enough on a college campus.
1mph is 264ft/minute. Reasonable walking speed is about 3mph, or over 750ft/minute. A safe bicyclist will cover that distance in about 20 sec, saving at most 10 sec.
Meanwhile, the walkers had a conversation.
And, since students have 10 minutes between classes, the time saving of faster transport doesn't buy them anything even if they're going 1,500ft..
That's why students who own bikes don't use them all that much. They're only useful to/from campus and for long-hauls.
Also, bikes need more maneuvering space than pedestrians. Not as much as rollerbladers, though. (Don't get me started...)
The majority of college students who walk between classes have bikes, so why would the availability of free bikes change their behavior?
Bikes are probably best suited to trips of about 1/4 - 10 miles, alone, with less than fifty pounds of cargo. (That covers more trips than many people realize.) Riding a bike three blocks is probably not worth the trouble, and riding fifty miles is (while quite possible) going to take a few hours.