There are many reasons why you might want to lock your SkyCart™, here are some of them:
You use it as your home bar and you have youths or adolescents in your household and want to prevent uncontrolled alcohol consumption.
You use it in your home office and you need to keep confidential business papers under lock.
You use it during a trade show and want to lock papers and utensils away while the SkyCart™ remains unattended during a break or overnight.
Beyond that, there are many more reasons to lock your airline service trolley. At the airlines they do it too. Typically, they do not use a lock but one-way plastic seals that will be broken by the cabin crew. This way it is ensured that no one tampered with food or drinks while the galley carts are on their way from the airline catering facility to the airplane.