Frankly it's rather cheap that Kaido was injured so quickly and early in the raid and by the Scabbards even if it was to hype advanced Coa.
But make no mistake while it's already an exploit to injure Kaido the true difficulty with him it's to make him stay down, it's surely not like Mr1 who was defeated as soon as Zoro learnt how to cut steel, Kaido has certainely a lot of endurance and badassery to show and he may be an Awakened Zoan user in addition.
Same for his Calamities who are most likely Awakened Zoans too, especially Ancient Zoans ones.
The situation may not look bad for the alliance but Kaido, Big Mom and the rest of the foes have not counter-attacked yet and neither Kaido, Big Mom or the Calamities and Flying Six have shown their true power yet.
Similar to the Fire Festival things are soon going to change and the alliance will find itself cornered and in a desesperate situation like at the Tea Party of Big Mom until the Tamatebakko bomb saved them from extermination.