The wizard raised the spellbook from the altar and spoke an encantation from it. Placing the spellbook back, he lit the candles and took his wand up in his right hand and proclaimed,"As in Heaven, so on Earth! As my Will, so mote it be!" Without an altar, the wizard would be scrambling on the floor for his tools and would probably be kicking things over. The altar is so much more than a table though. It is a sacred space cut off from "civilization" and of distractions where one can practice their Art.
Don't get me wrong, the altar is a kind of table and is used for holding things while you perform your chosen rituals. The placement of the tools on the altar is essential for a very practical reason: easy accessability of the tools for a smoothly cast spell. That isn't anything more than that.
The location of the altar is even more important. When choosing the place for your altar consider this: Will I be able to cast my entire ritual without interruption? Can I bet money on my not being interrupted and not lose my money by doing so? If you can answer yes to both questions, then you have found a good spot to consider. I say that only becuase it may not be a place that makes you comfortable. Many practitioners are adamant about having their altars outside, however, if you are like myself, you live in a cramped apartment and the outdoors are anything but private. The spot that you choose to place your altar needs to put you at ease and give you enough room to work.