[QuikAccount]

Not only is the product better, manga scanlators have a "code of honor." If a manga is licensed in English they will typically drop the manga no longer scanlating because there is now a provider in English. Of course, not all of them do this but more often than not it is adhered to.

[MichaelZuo]

Yes, this means that some clever folks realized they could have a legit manga website that removes the unlicensed translations the moment an official release is available. And they never allow uploads in the original copyrighted language. See mangadex.org

Idk who the founders are, or if it was a bunch of scanlation groups that combined their efforts, but it's a pretty smart way to get around the copyright problem.

[falcolas]

And until there is a company who has the license to publish in English, there's a benefit to the Japanese rightsholders - free and extensive market research.