@Sancturil
There's actually plenty wrong with this series, way before the issue of those "adventurer's" weapons.
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[*]Using a folding knife mid-combat, when she only had one hand to use. The blade's hard enough to extract one-handed when you're not being swung around by a gigantic wolf biting down on your arm.
[*]Her requiring grenade and RPG training for "self defense" in a medieval setting.
[*]Printing blueprints without even knowing the other world's measurement system (do they use meters? Inches? Goombas and Koopas?)
[*]Where did she get the necessary fonts anyway? Judging by her shop's signboard, the other world is clearly not using any alphabet used in our world. Is she a font designer?
[*]Getting simple carpenters to install electrical equipment. Where did they learn how to properly and safely handle it anyway? Did she teach them?
[*]Installing "various gaming consoles" in the other world, when she could just teleport back home to play them...
[*]People accepting her plastic-wrapped gifts without so much as a "WTF kind of material is this?"
[*]Nobody seems to be surprised at the fancy packaging in the first place, with all the extremely precise and detailed print.
[*]Selling flashlights in a world where electricity is unknown. Do these people even know what those things do, or why they'd want to buy one? And what about batteries?
[*]People using shopping baskets, as if it were a common concept in a world without supermarkets.
[*]Using a laptop, projector, microphone, and (invisible) speakers, when a simple painted (printed) canvas would've been much less likely to be questioned.
[*]Lending a freaking smartphone to take pictures. It's like she doesn't even care anymore that people could consider her a dangerous witch who needs to be eliminated.
[*]And after the initial surprise, nobody's asking about all that weird outlandish voodoo. As if the "foreign cuisine" is somehow more impressive than employing the services of a mage.
[*]Not to mention people seem more interested in buying fresh fish than finding out how she's shipping it in massive quantities. As if they couldn't ship it themselves and use the knowledge for more than just raw fish.
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If you're still expecting realism, you might be reading the wrong manga.