Double benefit from my perspective. I block people for three reasons, they are not mutually exclusive. Willful stupidity and being argumentative. If someone refuses to learn objective truth or insists I believe their objectively wrong position I have no need to interact with them in the future. I’m done with them. The third reason is getting the last word, myself or them. I have a hard time shutting up sometimes, so if someone meets either of the above criterial and has to continue to keep commenting on any rebuttal I make I just block them. There’s no reason to allow myself to continue the interaction, and the other person has no interest in a good faith discussion.