In the case of rooms or offices may have many people attend. Make money and resources required to perform the key up, back to sleep. If you have 10 users who would use up to 10 of the key, which is a waste.
Where the room or office There may be many people out. The need for keys, money and resources. For each sleep up to 10 users if they have to use up to 10 padlocks, which consumes significantly.
In the case of a room or office There may be a lender, a lot of people Make money and resources to do the key up for each user 10 sleep. If people will need to 10 padlocks, which is such a waste