When you puncture your soil - seemingly giving the same effect as Aeration - you are not actually producing the same result.  There are a few different elements that make up your lawn: the blade of the grass, the thatch, the root system, and the soil.  This is relevant because in a moment you're going to understand why a proper Aeration creates much more benefits as opposed to simply putting holes in your lawn. 

An Aeration involves the physical removal of anywhere from three to five inches of your lawn core.  These "cores" are the little dirt plugs that kids always throw at each other when they walk past a lawn that has been recently Aerated.  Removing the core creates several important changes in the lawn that are very beneficial. 

First, an Aeration loosens the soil beneath the grass and creates more physical space for the grasses roots to take hold.  Creating a stronger root system allows the grass to better absorb rainfall and nutrients as well as giving it a better hold in the soil.  The result is a more vibrant lawn- a softer texture, a deeper color, and a better appearance.  

Second, the cores on your lawn will redistribute the soil that has been taken up with them.  This spreads the nutrients on to the top layer of the grass.  This compounds the benefits from the last paragraph. 

Lastly, an Aeration breaks the thatch.  This is probably one of the most beneficial elements of an Aeration as, unlike a power rake or a de-thatching, an Aeration does not pose a huge risk to the short-term health of the lawn.  An Aeration can be done nearly any time of year (though it is the most beneficial in the early spring or just before winter) and can be done more than once.  Most landscapers are more than happy to do it more than once a year for you and may even encourage it. 

If you are in a dry climate you will benefit the most from an Aeration as dry climates are more susceptible to thatch buildup.  So, next time you go to puncture holes in your lawn just remember that you aren't really doing anything other than putting holes in your lawn... you need to physically remove the cores to get the full effect. 

You may notice your lawn to be a bit softer and be a bit more cushioned after an Aeration- this is because you have removed some of the hard packed soil and forced the soil to redistribute itself.  By loosening up the soil you have made your lawn softer. 

An Aeration can be performed in a very short amount of time by a professional.  An average sized lawn should take less than half an hour from start to finish.