Sure, Manga Plus by Shueisha is legal. It operates within the framework of copyright laws and partnerships with the creators and publishers to bring manga to fans in a lawful manner.
Shueisha Manga Plus stands out for its exclusive content and a user-friendly interface. Other platforms might have different features or a wider range of genres.
Shueisha markets their manga by creating hype around new releases, organizing fan events, and partnering with popular anime studios for adaptations. They also do targeted advertising based on the manga's genre and target audience.
In general, Shueisha is the owner of its manga. This gives them the authority to make decisions regarding its publication, adaptation, and other related matters.
Jump Plus manga encompasses a wide spectrum. Whether a manga is seinen within Jump Plus depends on its specific content and intended readership. There's no strict rule that everything on Jump Plus is of the seinen category.
Sure, Manga Plus is a legitimate option. It provides a legitimate and quality manga reading experience. You don't have to worry about any illegal or unethical aspects when using it.