agreed. i bought a bike off eBay with so-so components, mostly for the frame- i just needed something to ride, as my old rides were ill-fitting. and once i got it, i started swapping things out to my preferences as i figured them out (saddle, brake lever, bars, etc.)
for someone who is more seasoned with putting bikes together, the above makes sense. for those of us who are still learning (on a slow curve, admittedly ), having low-end components that allow us to just start riding and then figure it out from there are somewhat helpful. it lets one learn from experience what they like and don't like.