It’s pointless to the overall plot.
I don’t know if I would say that something is pointless just because it doesn’t affect the outcome of the plot. It did affect the outcome of the plot in this case, but even if it didn’t it wouldn’t be pointless.
You can compare it to the claim that Indiana Jones doesn’t affect the plot of Raiders of the Lost Ark. Even if he doesn’t, he’s not pointless.
You can compare it to almost any episode of a sitcom like The Simpsons where each episode ends with everything back to status quo, which means you can skip any episode and you won’t know that you missed anyhing. Still, the episodes aren’t pointless.
You can say that you didn’t like it, that’s fine, but that doesn’t make it pointless either.
I disagree. If you’re invested in the characters, yes then it’s not pointless. Most people were so invested in the character of Indiana Jones, they didn’t even notice he didn’t affect the plot. In this case I wasn’t invested in Rose’s and Finn’s mission, and since it didn’t really affect the plot other than to stop Finn from needlessly sacrificing himself (something that Rose didn’t know, meaning she would have doomed everyone, despite her save what you love speech), I watched a 30 min segment that ultimately didn’t really pay off for me, therefore it was a waste of time, and thus a pointless sequence.