Earlier quoted context omitted.
Ehhh… Sure you won’t convince the person you’re talking too, but it’s often worth it because if you really destroy their argument in a way that’s visible to bystanders, you could quietly convince a lot of them (since they can change their minds quietly without any ego cost).
I think when you "really destroy their argument," the average human bystander thinks "... what a jerk." If you quietly make a few good points, don't push too hard, and ask sincere questions to help you understand the other person's perspectives, the average human will think "that guy is a class act. He had a good point, too." Convincing anyone other than a hyper-rationalist of almost anything significant is more abou…
If that other person is being manipulated by cult like behavior from some other party it can be very difficult to convince them of anything. The other party has no problem with lying then doubling down on the lies forever.