Don't think I could be faffed with a bike for that kind of distance. I'd spend more time getting it out of the shed and chaining it up again than I would riding it.
I know what you mean, and if it's wet, forget riding! It only takes a minute or two to get the bike out of the shed, and five or six minutes against nearer twenty walking means the bike wins. And it gets parked at the bottom of a flight of stairs behind a keycarded security door, which I have to go through to get to my work area.
Plus my left knee is playing me up more and more after a me/tarmac interface three years ago, and gets really quite painful at the mo', so the bike is more comfortable. Going to get the knee checked out, but I'm afraid of what they might find, it looks more swollen now than six months ago