While forms are a fancy way to show the table, they are also a way for you to control what type of information is entered into the table, how the information is entered and forms give you the ability to maniplulate the information being entered with code. It will also alow you to protect the data that is stored in the tables from the user. You, as the developer have total control and the user gets an easy to use interface that will help them along the way.
In a nutshell the forms purpose it to make sure the data that gets entered into a table is accurate and protected.
I am no professional but I would never recomend giving users direct access to the data in your tables. By the way, you are not limited to using the forms supplied by Access. If you skilled in Visual Basic or HTML you can use either as a front end to your tables.