Even if your main source of income is something like affiliate marketing, it is suggested to still have your AdSense account and submit all the sites under your network for AdSense approval.
One advantage is a network site approved for AdSense means it is following good practices prescribed by the Google. You can be assured that Google Search has not found anything objectionable to be blacklisted on its search engine. This means your site has no serious issue that may otherwise compromise on organic searches on Google, thereby making the most of affiliate marketing or other revenue streams of your choice.
Also in case you are willing to sale your website on marketplaces like Flippa, an AdSense approved account is a big positive. Even if you are not making much from AdSense, buyer gets a sense of confidence.
Now, this post is regarding a perspective from a buyer of an AdSense approved website. I will proceed with a case study of website WooSplendid.com sold by me through marketplace Flippa.
Other things remaining the same, the buyer of WooSplendid intended first to have her own new AdSense account approved. The buyer relied on me to apply for her new AdSense account on her behalf. It is to be noted that an AdSense account is non-transferable. So if you buy an existing AdSense approved website, you still need to apply afresh for your AdSense account, and there is no guarantee that Google will approve when submitted by the new buyer. So be careful providing accurate details both on newly-purchased website and AdSense signup.
The About, Terms, Privacy, and Disclaimer pages were updated with details of the new buyer (company, contact person, contact email id, phone no). Actually, I was using Termageddon software for generating the policies. For example, this is Terms page of one of my websites, powered by Termageddon. For the buyer, I copied text that is loaded from Termageddon server and edited while making the text as part of the page. Of course, one is advised to edit policies as per the ways you are going to operate site going forward.
Applied for AdSense account here on behalf of the buyer.
Since for the WordPress website WooSplendid.com, I was using Header & Footer plugin for placing AdSense code, all I needed was to remove my AdSense code and place the same for the AdSense code of the buyer that is generated while submitting the first website for AdSense approval.
After AdSense signup and submission of website for AdSense approval, it is advised to immediately add Ads.txt file (though you can do this step later). Since I am using Ads.txt Manager plugin, I decided to update the file for the new buyer.
The AdSense account was approved within 72 hours of submission.
Here are the screenshots of my discussion with the buyer while in the process of applying a new AdSense account for her: