Curling iron question

I just spent 85$ on a curling iron at the hair dresser! I some times seem to get a little spending
crazy and dont even think twice about what Im buying.(impulsivness) Anyways I always go to the same hairdresser. Everytime I go he straightens my hair for me. This time he was using a 1 1/4 Babyliss curling iron with the hot air burst button. Im wondering since I dont ever curl my hair Why did he sell me a curling iron to straighten it? I didnt think of this at the time but dosent an actual straghtning iron work better? It cost me 90$. That is alot, Im wondering if I should have gone a cheaper route. It doesnt say anywhere about the product being less damaging then other irons but me hairdresser insisted it was ok to use everyday without damaging? This is one hot curling iron and dont see how it wouldnt. It does seem to work well getting it stick staright. Do other people use these as staigtning irons? Is there any advantages to using this iron? Also on the cord there is a sticker that says Not For Household Use, May Cause BUrns. I am curling iron incompetant, Do I have anything to worry about? Thanks for your help.