first its not compressed air, its some sorta chemical, ive known ppl to huff on "compressed air" cans, sry but huffing air doesnt give ppl a buzz
second comparing an air compressor with a pc case isnt even logical, case fans and cases dont compress the air, at least not noticably.
third, its a matter of opinion, and give and takes, blow it out with a can of stuff u make a mess and chance blowing even more dust down around the cpu and in connectors n **** when it wouldnt have settled there to begin with, use a vacuum and spaz and u will b buying new hardware.
btw turn the "air" can upside down for ur own homemade freezing gun. i had fun freezing all those damn japanese beetle thingys when they invaded my room and everyone elses last summer