Hi, regarding your question, in some places they already use that, they have small screens where customers order what they want, but they use a specific module for customers so they can easily see what they order or cancel the order if they make a mistake.
As for accounts for specific tables I don't know if it is possible, but maybe playing with Users, TableViews and Departments you may manage to achieve that, in any case it's a good idea already in practice, the only concern would be: users being able to use the system, the fact they may not be able to see prices before choosing a product, and make sure they don't have access to payment options.
Now, in a future version would be great to have a client terminal for a specific table or tables, where customers, or even waiters, can easily choose what they want and possibly see the price, I dare to say that it wouldn't be too hard to implement, let's hope we'll see that in the future