I don't see any negative effects in doing that. Unless your site is so "weak" the other page outranks your page for that keyword. If your site is relevant then it could increase your type in traffic as people copy paste the address into their browsers when looking for more information. How it affects the ranking... I would say it has very little meaning if anything at all. One should concentrate the energy to something more important, such as hyperlinks.
It's possible that this is one way that Google could measure brand - by measuring non hyperlinked URLs and trade marks etc they'd get a less manipulated SERP.
It doesn't help pagerank because its not a link, but as suggested by AidyUK its possible its a factor the big G considers, because it effectively is a link but the person has been too lazy to hyperlink it.
@driscto , i agree with driscto as the link is not clickable then Google will not be able to detect that link and give it a favor.
No, without the <a href etc in the html, the crawl bot treats the site name as text, so it is not counted.