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humbleoverlord You still need soldiers for that. Ask any modern army about their recruitment problems and you see the issue. Of course you can still forcibly conscript people, but it's easier when "you get some food" is a great incentive to go to war ...
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kazaddum I'm fairly sure ashigaru were essentially conscripts - true, not the same as peasant militia, but not like it was just professional samurai fighting those wars. Of course those are the guys always coming up in fiction (and history too, I guess), but you need someone to fill out the ranks.
Either way regardless of the exact mechanics content people are less likely to be happy to go to any sort of war where they might get killed and murdered for no real gain for them.