What Are the Main Factors Motivating People to Connect Buildings via Skybridge?

Bad weather and climate tat that's got to be a motivator, which is also true of places that have more underground tunnels connecting buildings together. And then, of course, you ace security concerns, like if you have high security government buildings or something,. i imagine they try to limit the necessity to go outside and enter a different door and do tha whole thing all over again.