Originally Posted by
ReiMakoto
There's a book in gubal library that explains some lore explanation. The reason iirc was the spells used to be called Cure, Cura, Curaga, but when a more powerful form of Curaga was invented, there was a debate on what it should be called, and they decided all the options sounded silly/ not grand enough, and if ever a spell was invented even stronger, it would be even more ludicrously named, so they swapped to a number based system for convenience, and so it was clear what was stronger than what.
Outside of Lore, I'm assuming they thought as in the western translations of some of the older games had numeric magic upgrades, the west would prefer it, but as the same time we've had more games with suffixes than numbers so its not like its a common trend