THE WORLD OF VOID:
I'll be explaining why the world of void is a void [do we even have standards for these?]
1- the world of void, by its name is a void, when we first saw it, we saw nothing in it. The clouds are an artistic choice so we can actually see the world of void [despite having nothing to see]. The are there so when the tournament can happen, we would ne able to see the fighters.
2 - the World of void is stated to be [either via GP or whis] or the null world " a world with no space or time, filed with eternal emptiness and nothingness". Pretty clear cut statement of being a void.
Counter arguments time!!:
"Hit can use his time abilities , meaning the null world has time". 1-No, it just means he can use his time abilities in a place without time. 2- he has stored time, aka he can use his stored time to use his abilities .
"Anilaza can bend space, meaning space exists" 3-that's true, how ever, when Goku visited future xeno, he was able to move, and use the time machine Freely, reminding you future zeno was floating in a place without space, time or matter, because space time was literally distroyed. before you stay. "Well then if goku can time travel to a place without time, then time is actually there" no. Because Zeno was repeatedly stated to have destroyed the entire timeline, even the time ring [Which represents timeline(s)] was destroyed. It's just that time machine can time travel to a place without time. And even if you aren't convinced, when two gods fight [Or just play slightly seriously ] it effects two separate space times, but when they fought in the null world, space time wasn't effected because it wasn't there. And even if you aren't convinced, GO could've added space time, but only to the stage as a part of his preparation [He even added gravity.]
So yes, the world of void is a true void., and zeno is able to erase/erased it [along the future timeline]. Why he is capeable of doing so? Because he was stated to be able to destroy/erase all of existence and anything he wishes in An instant, including the world of void.