You're absolutely right, IMO, to be more worried about theft from a car/house than a properly locked bike left for a reasonable period of time. If I had one super valuable bike, I might consider this approach...but I have a fleet. I rely on two things for protection:

1. Security (iron bars on back door, cylinders in the Windows, cameras).
2. Insurance.

We had a break in a few years back....they reached over the Vanilla frame, left the de rosa Titanio, Marnati, etc. and took the $600 TV, a 5 year old lap top and some dumb stuff. I guess just hope they don't know bikes!