Since when has she shown to be able to use Chakra Scalpal in combat? Even if she has it I doubt she would resort to it. When she is in Paper Coffin she can't get out because her arms will be binded. Konan can mix in paper bombs and deal some deadly damage
Katsuyu gets destroyed by either Paper Chakram Or paper bomb barrage
Most of her jutsus (Ex: Paper Shuriken, Multi Paper Bombs) don't take that much chakra. I don't think Tsunade will be able to keep up with all of the damage.
Tsunade used chakra scapel over her arms to help knock away the fire attack Madara threw at the gokage. If it is not chakra scapel it's just chakra cloaked arms. She will rip out of it not to mention she would have to let herself get wraped up in the first place.
Do you think paper coffin will bind a woman easily who has the power to lift gamabunta's sword? And make craters with her finger?
How can you assume she would not use chakra scapel just because it's not convenient for you, how biased. She will do anything it takes to get out.
Katsuya cannot die by bombs, homegirl tanked shinra tensei and all physical attacks. Katsuya has only ever died by having chakra absorbed out of her.
Byakugou > explosions. Everyone thinks because she has byakugou she will allow herself to take damage she does not need to, lets not forget using byakugou in itself is going to harm her in the end and the less damage she takes the longer byakugou could potentially last for her so she would still dodge.
Even though Tsunade getting damaged continuously in Madara fight was able to last hours.
Also Tsunade can use great division and have katsuya situated on different areas of the battlefield to provide Acid support and even provide defensive support.