Well from what I can see, Shizuko feels it is her responsibility to join the fight to take ownership of the weapons she introduced. Not only that but to protect the life she has built for herself and the people around her. That might also be why she so willingly shares her information, less damage if the ones who invade have already taken in some of Shizuko's policies.
I've understood that when she first took on her role as one of the leaders in the battlefield and even witnessed death firsthand. She participated with her uncle because of it, but the tension gets me so bad I wish she gives full reign to her uncle instead and focus on influencing the people more and more esp since most soldiers are common folk. She's good at building the economy and could probably stablize it for Oda (like the newspapers), so there's that yearning to wish she'd stay behind the frontlines（/TДT)/ coz look at these leaders having their eyes on her as Oda places her in the limelight more and more. Istg, the author makes me fear she'd actually die or be injured in the future.
From traitors to plain difference in belief or method, there's a lot of complicated interactions between leaders. So there's always that tension that the economy Shizuko is building will fail once other leaders try to mess with her community. I'd rather Shizuko focus on keeping peace with the people and leave the violence to her uncle...coz I see it with how she's slowly taking apart the notions of other people towards Oda with the newspaper. But everytime she shows up talking about explosives, I keep wishing she just goes back to being a farmer (but I know that Oda here loves to leash her ╥﹏╥)