How is text-based Q&A superior to opening up phone lines for larger audiences?  Let me count the ways.

You can them ignore them for a while without someone feeling ignored or passing out from holding their arm up for long.

You don’t have to use the phrase “parking lot” for a question that comes in that you’d really rather answer later one-on-one instead of in front of the group.

You can pick/choose the questions you want to want to answer.

You can better manage your time.

You can use planted questions more easily (nobody actually even has to ask the question).

You can tackle managing them as a group.  For a big audience, you can enlist additional people to join the presentation team to answer questions.  Let the event producer or moderator or sales team tackle those FAQs that would otherwise take up your time.

Master the essential tool for interactive presentations.  Master text-based Q&A.