The burden of previous knowledge is so great that unless you made it unmissable or tutorial-levels of obvious, who cared? Most Blue Magic sets are crazy overpowered, but the biggest problem is that you have to get hit (and usually survive), assuming that you even know that those spells existed in the first place.

Also, most FF games are balanced around not having access to any of these spells. Only time I used Blue Magic on a first playthrough was in FFX, because it gave Kimahri his Overdrive immediately when you learned a new one.