you win rng the spirit is willing but the flesh is weak

[ToasterMan]

I used to do that, but that was when the extra stats from the pentameld REALLY helped or outright made certain actions too RNG without it (like macroing certain rotations). Right now, unless you're trying to min/max for completion sake or want to save some gil by using lower tier materia throughout, you really don't need to do it. IW gear really does make pentamelding unnecessary, albeit quad is still certainly a thing lol.

It's likely that you'll have to do it so you can meet the stat requirements for the 4 Star recipes that haven't arrived yet.