Air in the atmosphere that we breathe is essential to life on Earth. This is true not just for humans but all Mammalian, Piscine and flora life. We don’t just use air to breathe. Air pressure and Wind pressure have practical applications in terms of industry. For example, Vacuum Conveying like that available from https://www.aptech.uk.com/pneumatic-conveying-systems/vacuum-conveying/ is used to push products through tubes.
We also use air to inflate things to increase their size and mass. Two uses for this are the Hovercraft and the use of small balloons in medicine to open arteries in the body to increase blood flow.
Earth is surrounded by a blanket of air about 400 miles deep. As you get closer to the edge of the Earth it thins out. You might think that air is light as you cannot touch or see it but it is still able to exert a pressure weight on everything on Earth. It’s the same as if you were in thirty four feet of water, which would prove fatal. We don’t notice when Air presses on us as it does it equally from all sides and the liquids in our bodies press back. Also, Air molecules are not as dense as water molecules.