If you don't do a fishless cycle, you will skip the boredom of watchig an empty tank for a month and replace it with the anxiety of waking up each morning hoping you didn't lose another fish.
Fishless cycles are always a good idea because they prevent death, they prevent disease (unless you want to quarentine your cycle fish), they give you time to research the species you want to keep, they allow you to landscape your aquarium the way you want before adding fish (it's a pain after adding them), and it's cheaper to buy ammonia than it is to buy a bunch of "cycle fish".