Q: Will Press Releases distributed by 3rd party vendors help with SEO for my website?
A: Interesting question. Obviously, one should post any press releases on their own website for SEO and, more importantly, consumer value - that's a given.
So then, if there's duplicate content on the web, that's a negative. The search engines require that the original source of content be identified (coded) as the "canonical" version. So if it's not to live on your site but rather on the vendor's, then you lose the SEO value of that content for your website.
Note: these paid press release distribution services are generally downgraded links in the view of search engines. In fact, most of the services put in code to counter SEO links ("no follow" or robots, don't go or log the linked website), so, no, press releases are not beneficial for your SEO (but could help the press release vendor's).
no, press releases distributed by a 3rd party vendor generally are not beneficial for your SEO
Press Releases, no matter which platform, should be for the benefit of the user, never to scam the system! If you want people to be aware of something newsworthy that will benefit them or that they need to need about, then use a press release service. This might be a generic service like PRNewswire, or a media organization serving that industry. Appropriate content for a press release might include personnel changes, new product releases with why it matters to the reader/ what problem it solves, etc.