I haven't got these yet (they're available just don't want to spend all of my yen), so maybe it doesn't matter, but these almost feel like a bit of a cheat. SP works differently than MP in most games - it's really important and is the main limiter on you just running through enemies, since everything has a weakness and the strategy of when to use your SP is part of what makes battles a challenge.
Also, it adds some fun tension to dungeons when you try to one-shot them and by the end are scraping for a few points of SP however you can get it.
Seems like regenerating SP (dunno how it works, per turn i guess?) would kill some of that, since the scarcity of it is what balances out how easy enemies are to kill.
Then again, who cares. I'll buy em anyway.