If it improved page load performance, then why wouldn't you do it? Make sure to test your sites on slower / limited types of hardware if you're using a beast of a machine for most of your work / recreation. That should go without saying, but recently there was an interesting Hacker News thread around a link to a blog post concerning why the web is so slow. Apparently not everyone agrees and experiences differ wildly.
I'm in the camp of having a feeling of slow load times, which could be for any number of reasons from connection strength to system limitations (new cheap chromebook). One of the most frustrating experiences is when I can't scroll a page due to loading, where it seems like I should be able to scroll the page. Not sure how much of that is one side or the other, and if it's on my end, I'm not sure how much of this could be helped by how the page's content loads, but half the time it seems like most of the content is there, yet the loading thing spinner is still going on my browser.
Another annoyance is scrolling down the page and then being thrown violently to the top of the page because something new loaded. I assume maybe this is a page reflow? Not sure. I'm still new to web development.