Kid Buu was the greatest threat to the universe before Zamasu

[apex_pretador]

Now that I think about it,

Freeza just wanted to control the universe, destroying a few planets which get difficult to control. No damage done to Universe, instead an order established.

Cell just wanted to seek out strong competition in the universe and destroy weaker beings, possibly destroying some planets. He might've found that competition in form of dabura who might've taken care of him. Otherwise Beerus could've sneezed him away when he woke up.

Beerus wasn't a threat to the universe, he had a job to this universe. Sure, his and Goku's fight endangered the universe but he himself also did somthing to help avoid that (nullified that energy of beam clash)

Golden Freeza could've been erased by Beerus on spot if he wanted to, or later.

Kid buu on the other hand, blew up the earth and teleported to the kaioshin realm. If not for Goku-Vegeta-Fat buu being able to barely hold him off, he would;ve won. Hell, even in the middle of the fight, he could've blown the planet up. Goodbye Goku, Goodbye Vegeta, Goodbye kaioshins. Their death would also mean deth of Beerus and deactivation of whis. And if this is after Shin teleported to Namek, it is even worse, since he could teleport to Namek and then blow it up alongwith shin, beerus, dragon balls and whis.
He could;ve then teleported back to earth, blow it up again and go chill around blowing up planets. He would've been unstoppable. And if we are counting anime filler, he could've teleported to otherworld, blow it up and kill already dead beings, erasing them forever.

And Zano or grand priest won't interfer, like they didn't in Goku Black arc. Maybe when Champa comes looking for Beerus and goes back when he doesn't find him, thinking he is off somewhere? Maybe Buu blows up a super dragonball accidentally before Champa even starts to finds them, therefore deactivating them all - leaving champa no reason to come into U7? Then he continues to blow up planets for an eternity.

[Dragonballgod19]

Yeah agree

[Meshack]

And Zano or grand priest won't interfer, like they didn't in Goku Black arc.

Zenoh and Daishinkan did not interfere because Whis and Beerus warned Goku not to because they would get angry about it or something. However, the future Zenoh interfered when Goku summoned him at the end of the arc.