Just reading a forum like this how many skill rolls do you think we do? Let's consider the situation here, yoou both have your positions, each of you has tehir own arguments, both of you share the same goal "convince" the counter part of the consistence of your position.
How this play if modeled? First poster makes the statement, second one makes a roll on persuation, lets make it a slightly succesful one (just because there is a response that is not irate or annoyed, signs of a natural 1 on persuasion :P

), you made an objection your "antagonist" try another argument thus making another persuasion roll.
The tadpole situation was done in the right way because it showed how the ones in the characters are attached to life, in that scene I was controlling Arastos, a man who is decided to get rid at any cost of the parasite in his head, still it was difficult (aside from my luck, in my tabletop rpg sessions I was famed for being a nightmare of consecutive natural ones, in Vampires The Masquerade I was able to queue six on a row, my narrator was desperated because he had planned some critical failures but not so much

)for him to kill the vermin not because Larian wanted him to fail but because they wanted to show something.
Furthermore they use the consecutive rolls only when the other part is determined as the main toons are. Nettie and the tadpole are exemplar, in other cases (when the characters are more determined or the rolls are on actions and not words), furthermore they sometimes gave you more possibilities based on your skills and profiencies, because just like in real life in a conversation we can shift strategies from persuation to deception or mix them, if a strategy you're using fails you can try to change it.