None of these are counterarguments
> Maybe they want to make sure you're there
There's not even an a real scenario here
> maybe their issue is dependent on the time
"Hi, I have a time sensitive question about X, are you available to help for a minute?"
honestly that's much more likely to get a response from me than "hi" anyway, because I know it's urgent, assuming you're not someone who abuses the idea of urgent.
> maybe they want to send/receive a TOTP
"Hey, I need a TOTP real fast, are you around?"
And my response would be "no, I'm not sharing my TOTP with you" but alas
> maybe the whole point of the conversation is to check whether the medium is functional
"Hey, having trouble with Slack today, are you seeing this?"
Again, I'd be much more likely to respond than just "hi" that might turn into a real time suck for me
> maybe they want to send you something sensitive
"Hey, are you screen sharing? want to send you some budget numbers"
None of these are improved by just saying "hi"