BLM actions

[Michelasso]

Maybe it is a dumb question, but still I have to figure it out. Aren't the BLM job's actions a bit useless? Apart from Manawall (nullifies two phys attacks) and maybe Flare (I am closed to get it).

Convert sucks HP to get MP. Why would I do that if I can get all the MP I need with Ethers and then cast Blizzard III?

Freeze I still have to understand what it does so special.

Apocatastasis shields a bit the others, one per time, from elements. And only for a short time I mean.. It is a Black Mage!

And I lose Protect as a cross-class action. Am I looking at them in the wrong way? I never use the 3 above.