Is there an SEO or pagerank benefit in grouping (rel="alternate") multi-language websites (using multiple domains) together?

Question

I'm building this website that will be multi-region / multi-language.

And for that, Google suggests the following:

https://support.google.com/webmasters/answer/182192?hl=en

Since, my domain will have to change based on the country language, I'll have to go with option #1.

A country-specific domain.

Example:

• www.name-in-english.net
• www.name-in-deutsch.net
• www.name-in-spanish.net
• www.name-in-french.net

Since they all have different domains, if I don't let Google know that they are the same website, they will all be treated as single unique websites.

Google suggests that you can "group" them together using one of those 3 options:

https://support.google.com/webmasters/answer/189077

If I'm doing it, I'll use the Sitemap option.

But my question is:

What do I gain by letting Google know that all those websites are the same one, but in different languages? What will be different if I let Google think that they are all single unique separate websites?

Do I gain some SEO or pagerank by doing that?

I mean, what if I get great traffic from my english website. Does that benefit my other languages results in the other domains?

Answer 1

John Mueller from Google answered this to me on Twitter: