Google tends to hold new websites back so that it can check whether they are legitimate or not, so some people bought older domain names as a way of bypassing this process.

But Google is smart so it can start the process again once a domain has been bought by someone new. So there are some advantages to having an older domain name,but it's not a guaranteed method.

(It is the reason why you should try and get a site published and live even if there isn't much content on it so that it can begin going through this holding process as soon as possible.)

None of that process has anything to do with affiliate links to WA, google recognises sub domain names like siterubix sites as being separate sites.

On a separate note PBNs or private blog networks are when the same person owns multiple sites that all drive traffic and provide backinks to one main site. WA is not a PBN it is a hosting site, individuals within it may use WA as a platform to develop a PBN but that is an individual problem and Google will penalise them not WA or the rest of the members.