Comment by kapildev

One valid reason I have seen of people just saying "Hello" is to see if they get ghosted after putting their request. There are some people who can't bring themselves to say "no" and want an escape saying "Oh, I have not seen your messages" or something like that. For those people, hitting them up with "hello" and then putting the request helps narrow it down for you that your specific request made them ghost you and not them being busy.