This is double blade sword. You may look into taxi drives cars and think - this is good, reliable car, with low maintenance cost if taxi drives, who drives those all day is using. I know in poorer countries this research for new car happens a lot.
Hey Ifx, the saying is "double-edged sword" not "double blade sword" [0]. Just letting you know in case English is not your native language. Personally when I am learning other languages I love to be corrected. Feel free to ignore this - you have the right to say the idiom any way you please.