Would you buy a pair of speakers by just looking at the measured freq. response?

Yes It’s true that precision microphones used to measure frequency response tell you nothing about how speakers sound. Go figure! 

If measured well that would absolutely influence my buying decision all other things aside because I have been around enough to take that info for what it’s worth but buying any speakers without hearing first is risky business. If you do it buy used so can resell or buy with a suitable return policy only.  Otherwise be willing to take a financial hit especially for pricey high end items.