A fast-loading site is a good thing. Your site's speed matters. Which is why creating fast sites is one of Nikola's design goals.
Sure, it's not meant to create e-commerce sites, but if you are doing just a simple corporate site, or a personal blog, why would you not make it as fast as possible anyway?
So, here's one data point, from Kay Hayen
But you don't have to just believe that graph. Here's Yahoo's YSlow report on my personal blog, which is hosted in a $5 VPS (as is this site, BTW. The same VPS. As is a bunch of services. And my Quassel core)
It scores 94 on that test. That's 94 out of 100 possible points in the "Small Site or Blog" ruleset.
How much server tuning was needed? I added one line to the Apache config:
AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css
That makes it compress those files before sending it to the user and improved the third item from F to A.
So, when I say Nikola makes your site fast, don't take my word for it, just check it out.