Because it is normal. Even without domestic abuse, women have been financially dependent on their spouses for most of history, and if you're not financially independent, you're completely fucked if anything happens that the breadwinner is no longer sharing bread, whether that's abuse, divorce, family abandonment or he gets randomly struck by lightning. In the old days we had dowries for that, but even then there was nothing but social disapproval to stop a shitty husband taking it and spending it on himself. Everyone should have an emergency stash. Even if you have your own job, even if you're the primary breadwinner, if you don't have an emergency fund stashed someplace outside the joint account, your ass is hanging out.