Selected answers from the Dumb SEO Questions G+ community.
Christopher Fleming: I`d expect a lower bounce rate would be number one. Also possible increase in page views.
Casey Markee: "An eCommerce website with page speed 3 seconds or more yields 22% fewer conversions than an eCommerce website that loads in one second."
And that was in 2013! I`m sure the increase now is substantially higher.
Michael Stricker: Whatever the advantage is, it multiplies with each additional page... since B2B tends to be a content play, more pages per session, more downloads and more return users. But, alas, I cannot quantify so specifically.
Dave Elliott: Google released quite a nice basic benchmarking tool about a month ago www.thinkwithgoogle.com/feature/mobile/
Travis Bailey: People are impatient and faced with a lot of distractions. A performance increase of a couple seconds could be a marginal win on a low volume site. Or, it could it could be a massive win on a high traffic site.
Either way, people like pages to load as fast as possible.