When using canonical URLs for web content, more info can be shared to improve the site SEO.
I've added article title as a page subtitle, the summary as page description and the article tags as keywords.
Steps to test this:
1) Install a SEO analyzer tool (like "SEO for Chrome", "SEO Helper Tool", "SEO Site Tools".. )
2) Create a display page (Add - page - content display page)
3) Create a journal article: add title, abstract, display page and tags - publish it
4) Click on edit - display page - "View content in XXX[PAGE NAME]"
5) The url that you see should be something like "http://server:port/web/guest/-/miArticle", which is the canonical URL of the article. That is the url you should analyze with the SEO tools
You should be able to see article title as page subtitle, the summary as page description and the article tags as keywords.