I appreciate this question, @CarsonWeitnauer. The struggle for people new in Christian apologetics is that they feel they absolutely need to have an answer for every question. It’s a good reminder that the faith does not stand or fall in our defense of it. It’ll remain to be true even if we fail in our apologetic.
To answer your question, for me, the benefit of saying that you don’t know is that it removes the pressure off you in providing your burden of proof. This reminds me of a skill I learned from Greg Koukl. If you are in a scenario where you feel you don’t know the answer, and the other person knows so much more than you, instead of fighting them head on, you could switch to fact-finding mode. This will shift the burden of proof on the other person, which will help you understand more their position, then maybe give an answer after you understand it better. If you don’t know the answer still, you can just say that you don’t know, then say that you’ll think about what they said and get back at them. This removes the pressure off you, and this helps you search and have a time without pressure in thinking about what was said by the other person.
Aside from that, this gives us a better witness. Since people will see that we are intellectually honest and that we are willing to admit if we don’t know. This will help them see that people engaged in Christian apologetics are not deluded fanatics, but really people who are willing to follow the evidence where it leads.