I find the styles differ based on a few factors: if someone says hi because we don’t work together very often, that makes sense. My teammates usual just throw the whole request into the hello. There’s also the issue that if I don’t answer immediately the initiator might need to find someone else. If they write their whole request out and I’m not there, it creates a demand incongruity especially if I try and work it (or provide an answer) 15 minutes later but someone else is already on it.
There’s also the factor that sometimes the person you need help from is the same person who has 40K unread emails in their inbox and doesn’t make it to all the meetings they accept. That’s another issue, but those people are also the kind of people who are subject to the most varied attempts at communication initiation.