Why didn't South and Dai Kaioshin use the potara against Moro?

[SSJ2]

They were complaining about being powerless against Moro if he continued to absorb energy and yet never thought of using the potara. On that note, why wouldn't they have used them against Boo either?

 

[Evil Vegeta]

Honestly, that's a good question. Maybe they felt as though the Fusion route was too extreme. SK's words makes it sound like he still believed they had a chance against Moro as long as he didn't continue absorbing energy.

Whatever the case may be, they certainly were having a hard time dealing with those comets and thunder blasts Moro was doing. If Dai didn't have that sealing technique, they would've been done.

When it comes to Boo, that's another mystery. In the Anime's depiction of Boo's attack, none of the Kaioshin were together when it took place. That's probably the best explanation. Or SK might've been doing well against Boo, but got absorbed quickly.