The depiction of characters wielding big swords in anime is primarily a stylistic choice rooted in the medium's artistic and storytelling conventions. Here are a few reasons why big swords are often featured in anime:

1. Visual Impact: Anime aims to captivate viewers with visually striking and exaggerated elements. Large swords provide a sense of grandeur, power, and spectacle. The dramatic size difference between the character and their weapon can enhance the visual impact and create a memorable image.
2. Symbolism of Strength: Big swords are often used as symbols of strength, prowess, and heroism. A character wielding a massive weapon signifies their exceptional power, skill, or determination. It visually communicates that they are formidable or capable of facing significant challenges.
3. Enhancing Action Sequences: Big swords in anime contribute to dynamic action sequences. The exaggerated size and weight of the weapons can create visually impressive and acrobatic combat movements. The action becomes more intense and visually engaging as characters swing, clash, and maneuver these massive blades.
4. Characterization and Design: The choice to equip a character with a big sword can be part of their overall design and characterization. It can represent their personality, role, or background. For example, a stoic or serious character might wield a massive sword as a symbol of their unwavering determination.
5. Homage to Fantasy and Gaming: Anime draws inspiration from fantasy literature, role-playing games, and other media where characters often wield large weapons. Big swords in anime can be a homage to these genres, paying tribute to iconic characters or archetypes.

It's important to note that anime often takes creative liberties, favoring artistic expression and dramatic impact over strict adherence to realism. The portrayal of big swords should be understood within the context of the anime's fictional world and the medium's penchant for exaggeration and stylization.