PR is done only when a business/site has something worthy to tell the public, it is more like a news and not just an article (both are two different things).
It should not be over done, once in a while will do but not often times.
Press Release is lots and lots of helpful in seo, as it increases the brand awareness, and if site is going to launch a product or as something to tell about the site then PR is helpful for the public.
Hello, I think press release promotions is the great way for the promotion of your website. But mostly press release sites are paid and charge huge prices which is why marketer prefer blog and article promotion most.