I think those are related. Spending lots of money brings votes, which is why campaigns spend so much money. Historically, Dems outspend Republicans, this race will be the opposite, Trump will outspend the Dem candidate, and a lot of that has to do with his VP pick.
Additionally, Vance is smart, a great speaker, young and energetic and completely aligned in policy with Trump. I actually think it is refreshing that the P chooses a mini-version of himself as a VP, rather than going for something opposite which is the traditional way. Hey, vote for me cause I am great, but just in case, here is my VP who is very different (the most extreme being centre-right Joe McCain choosing a lunatic far-right Sarah Palin). Basically, I think that Vance and Vivek policy and money wise were by far the best picks. Maybe Youngkin would have been strategically a great pick too cause if he takes Virginia, it is game over. But Rubio et al., I do not think so. You cannot run with a the uniparty is evil, bllah bllah bllah, and then choose Rubio as your VP. Especially when you're old yourself, which means that the successor is very different to you.