Tablets are a waste a money while at the same time not a waste of money. It's like buying a piano or guitar and not knowing how to play. If you have no intentions of playing then you wasted money. If you have intentions then it's a gamble. If you know how to play then you didn't waste money.
If you're not going to use it to basically draw and enhance your already artistic ability further with collaboration of a computer then you're wasting money. It all depends what you're going to use it for, buying it will not make you better. In fact even if you can draw on paper it will still take some time to get used to. All in all this is a circle argument and really no one is right or wrong.