I am not thinking that the POS part is as big of a deal as the accounting portion.
You have a day's worth of customers paying in Bitcoins going into a wallet and you have to trust an employee somewhere not to access that wallet and copy it onto his home computer. That end of things needs some work.
Right now it is ideal for a small business with a single owner.
You can route all your incoming payments to a offline wallet, only authorized person will have access to it.
Similarly, employees cannot initiate transactions or have access to the business bank account.