It is impossible to hold a good sitting on the floor. It causes you to lean and hunch a great deal and can strain your back. It also reduces blood flow through the posterior region that will put your legs and buttocks to sleep. You will also get pressure points and other aches and pains from it.
Carpet does not make a good work surface for any craft activity. It is difficult to get a good crease on carpet and static buildup, especially during the dry winter months, can affect foil wrapping.
Kneeling for long periods of time can cause a lot of aggravation and pain, especially if you are not use to it. You'll be using different muscles to keep your balance and they can quickly tire and get strained. You can also develop Bursitis of the knee if you kneel on hard surfaces.
Lighting levels on the floor are also lower than at most work surfaces and your worksite may be dimmer than you need.
If you must wrap on the floor at least sit on a pillow or cushion.
