Doesn’t help directly with anything, but indirectly.

I’ve met nearly all my friends in first-year 14x courses and they are some of the brightest minds in math/CS, who go on to have great jobs. You’ll motivate each other and benefit each other in terms of network (who’s hiring, interview tips etc. you can pretty much guarantee there’s someone who interned at the place you’re interviewing with). This is especially important since we don’t have a cohort system like in engineering. Folks who take 14x are somewhat of a cohort.

Knowledge wise, 14x is much more proof heavy vs. calculation heavy in 13x. For me, 13x would have been more, and boring, work. They can somewhat help with upper year classes, especially the theory heavy ones (STAT 330, 333, CS 485, etc). 14x is stressful though, in the sense that you can stare at a problem with no clue for hours. This is when friends can help. I’ve stayed up till 6am working on assignments with friends multiple times in my first semester but taking 14x was still the best decision I’ve taken since university.