Is there any benefit for you to habe other people comment? I mean, we are reading even if we dont write anything.
I can think of two. First is that it shows lots of people are reading the manga, which can make a difference in whether someone decides to start reading it or not. (If they see the latest chapters having 30+ comments vs less than 10, they're more likely to think "People really like this, I should try it out."
The second one is that it shows the translator that people are reading and appreciate their translations. Think of commenting as a small reward for their efforts. Similar to when someone (friend, coworker, boss, total stranger) compliments or thanks you for something you did.