Few people host their websites as hidden services because it's just asking too much from anyone who uses your site.

Imagine you are in a conversation with a stranger. You want to show him your personal website. Consider the following two sentences. Which has the highest probability of actually helping him getting on your website?

"Go to myfirstnamelastname.com. Yeah, it's spelled with a K."

"Go to $FIFTYSIXRANDOMCHRACTERS.onion. Oh you need to use the onion browser. Let me help you install it on your phone. Can't find the service? Oh my bad it's actually $FIFTYSIXRANDOMCHARACTERS.onion. There you go."