Then all 20 people get to see it at once, they can see if someone else already responded and other people on the team who may have been wondering about something similar also get to see the question and the answer(s).
Asking someone directly almost always results in a quick response, even if it is a "I don't know" answer. And an "I don't know" from a senior colleague can mean a lot, for example that the problem is much harder than you initially thought.
Ticket or bust. That way the question can go the proper way from cheap junior supporters to expensive senior ones (if necessary). It can be prioritized, subject to an SLA like time to first answer or time to solution. And the whole ticket can be searched and reused as documentation for identical/similar questions.
There is also the bystander effect - i.e. yelling call 911 vs asking someone directly to call 911