I disagree with the 2 comments above me. Tsunade is unkillable rounds 1-2 and can revive, plus she heals a lot too, karin just gets more of them. Karin is nice dont get me wrong, but as a support ninja she wont have the most stacked equipment so 1 immunity suppression or someone with higher init who targets karin with their msytery and she is done 2% life recovery on a 3rd or 4th pos ninja isnt really enough to keep them around for long

Tsunade can turn the tide of fights, anecdotal as this is the only karin user I personally have had any trouble with was some s 15* mega whale running madara ten tails/madara gnw/karin,

You have probably seen a lot more tsunades in action than karin, thats for a reason.

Also battlecrier is right that tsunade is in other events, but thats purely because she was released before karin, both will be available in other events sooner or later, but at this stage of the game tsunade is more dependable.

On this topic, does anyone know if karin's bug ever got fixed?