Several companies tried this for distributing software.
It was very controversial. Users were angry that software companies were using their internet bandwidth to distribute their software. Made a lot of people angry.
If only Blizzard servers were seeders, and clients were only leechers, that'd have not been a problem.
Typical example to show that people who want to be angry will be angry, even for pointless things.
>software companies were using their internet bandwidth to distribute their software
If I understand the description correctly, microsoft still does this!
https://support.microsoft.com/en-us/windows/privacy/windows-...