It's not that good. It's complete garbage, especially only healing for 20HP...
The bosses deal at least that much, so you're not making up any ground in order to survive.
Edit: how the FUCK are you supposed to beat
? Seriously, their dmaage is fucking insane for the level and lost abilities.
Edit 2: Wow, that was a lame boss fight. Beat them on my second try. But Dazzle and DEsperate Hits are disgusting to fight against. Had to pray that they wouldn't kick my ass, and still lost Maribel. Salvation Stone was next to useless as I got more reliable 30HP heals from leaves.