I don’t know how a back-link from a Private Blog Network (PBN) that talks about travelling would help a tech site to get a boost in ranking. Yes it may help, but not for a long period of time time. When Google knows that these back-links are not relevant, it smashes you down.
That’s why asking for samples before buying PBN is a must. if I was wrong, please correct me!
You aren’t wrong, but at the same time these non niche relevant PBN’s shouldn’t be the sole life blood of your back-link profile. Rather, PBN links should be complimenting your overall SEO strategy. These links should be mixing in high TF and DA back-links with your foundation links, press release links, and guest posts on niche relevant blogs. Remember there is no one back-link to dominate them all – instead think of each back-link as a puzzle piece of the bigger picture.
All top websites that have a da of 90 and above have links 1000’s of links from all over place run a back-link check on the highly ranked Gumtree every year 1000’s mention them with a link in all types of forums and niche websites so not sure at the moment.