Is it important to get ranking for each page of a website?

[Jake]

It's generally advised to get backlinks to multiple pages, in part to have a more natural looking backlink profile, some create a separate dedicated page featuring a different keyword, ultimately the more content you have the better chances you have of getting long tail keyword matches.
These days it's best to have removable links so you can better respond to a dreaded "unnatural link patten" warning being seen more often lately, you can always change the url of an inner page as a last resort to "shed" all of it's backlinks, you can't as easily eliminate bad home page links.