Unlike scarecrow which can only be used when sustaining direct damage , which means all your opponents monster has destroyed yours and you have taken a lot of damage already, waboku protects your monsters and prevent damage
The downside ? If opponent randomly shiyu it you can chain it but then opponent won't commit to make huge field. However after that they will just xyz photon streak bouncer instead of atmus and try to control from there. Which means Insector bombing can only occur successfully when you have another call of haunted or reborn or thunder break.
But with scarecrow you can do Insector spam next turn. So both cards have their upsides and their downsides. Which is better ? Your call.