Because time was pretty words were all it took to rank in Google. But with Google's Panda algorithm ruling the roost since 2012, an understanding of tone, voice, syntax, grammar et al, is now just the beginning. Write badly and you'll get penalised by Google. Write well and you'll get prioritised by Google.
'A picture is worth a thousand words' is an idiom we all know. But when it comes to ranking your website in Google search, give me a thousand words every time.