They are licensed & provide ongoing tech support as a part of those agreements.
It really depends on the POS system but for the most part they are pretty user friendly.
Each step of the way does require manual approval, so stock doesn’t just update itself until someone approvals the receival of it, that way if something doesn’t come etc. you can edit the receiving order (1 case of vodka arrives instead of the 2 cases your ordered). It doesn’t export for payment until someone gives it the all clear, doesn’t actually schedule the payment until someone says yes, that amount on that date is correct but those steps are all as simple as 1 click of a button after a quick double check.
You can knock out the whole businesses ordering/receiving process in about an hour if you know what you are doing.