Overwatch wants to be an eternal competitive game. It cannot be done without a stable and huge OW audience. And ordinary listeners can't even watch live broadcasts, how can they become listeners?
The fifth advantage: it is beneficial to collect data, improve heroes, and develop data media.
Today's era is the era of data. The most reliable feedback for the balance of the system is data.
Data is very important. The data is recorded in detail and constantly updated. The best example of development is probably the most powerful one in the NBA.
Because players can choose each hero to match freely, Blizzard can collect data to know which players like most;
Since players can switch to another hero after playing the ladder for a period of time and feel uncomfortable, Blizzard can use big data to analyze why players switch heroes;
Since players can BAN people before the game starts, Blizzard can collect data and analyze why players don't like or worry about a certain hero;
Please note that Blizzard's previous game balance has always been based on top players. While balancing the game based on top players, it is easy to ignore the experience of mid-to-high-end players. For example, Symmetra after this enhanced rework is a hero that destroys high-end game experience.
And Blizzard can fully collect the first feedback from players of all types of heroes in the full segment of players when they are serious, which will help the future updates of the game without any harm.