Technically, the only thing anyone can do with piety and tenacity materia right now is exchange it with Mutamix over near Uldah for other random materia. Hard to believe it has almost been half a decade since the community started saying that the spell speed, skill speed, tenacity, and piety materia are basically worthless or just niche and can be removed, yet they haven't bothered doing so.

However, I feel like the entire materia system is a nostalgia bait trap that SE fell into with FFXIV that they should have just killed on the onset when they went to 2.0. I lived through the "Final Fantasy VII" saga of Square Enix's development cycle and I for one was never a fan of FFVII. It was a tech demo for the original playstation that a lot of millenials grew up on and that is all there is to it. In fact, it was quite a boring game back in the day and it was mostly a time filler until other games came out like the 3d platformers and adventure style games. Technically, the biggest problems with the past two expansions has been relying way too much on nostalgia of past experiences to get sales. The entire reason that final fantasy games succeeded was because they brought outside experiences and made them their own.