It depends on your PBN. Too much misconception around PBN's these days. What is a PBN site? It's a site designed with the focus of linking to your money site to improve its rankings. If your network consists of sites with a WP theme and a bunch of articles slapped on, then adding natural content probably won't do any good since your site is at risk from being penalized anyway (a few second review or glance at the site is enough for someone to spot it's a shitty PBN). Just a waste of time.
However, if your network consisted of
real sites that provide real value and do not look or feel like the typical shitty PBN, then adding natural content is the best thing you can do. My private PBN's used for my own money sites are set up as real sites, with lots of 1k+ word articles that provide value. I do 1 long form content per month. I guarantee if you do this for a few months you'll quickly see your PBN sites getting organic traffic, organic rankings + providing you design them as real sites with real intended value, you'll never have problems with it.
After all, they're real sites. You won't believe the # of emails my PBN's receive every day from large SEO agencies proposing their outreach.
Of course, doing such a set up is time consuming, expensive and probably not worth it for a lot of people. However, in my specific case, the extra time and money that goes into the set up always pays off for my long term money sites. What would a real site in the niche do? Replicate their thought process.
Never make it about you - but rather switch the focus into providing value for users.
Some of you may say "but that's not a PBN.. that's just a money site" and you're right. A well designed network should essentially be real money sites. A PBN doesn't need to be shit quality - this is where all the misconception is.
As long as the sites are set up to pass link juice to your money sites, it's a PBN. However much you want to disguise it is completely up to you. I go the extra effort to ensure all the sites are real and provide value (essentially mini-money sites on their own). Yes, the set up/recurring costs can get expensive... but remember as these sites get stronger, so will the juice passing to your money sites.
However, as I said it all comes down to your exact requirements. If you don't care about longevity then you probably don't need to go to such efforts in setting up your network. Everyone has their own conditions.. you need to pick the best option
for your circumstances.
Look at what sites like Cosmopolitan, Marie Claire, Woman's Day, Elle, etc do. If you know what I'm talking about here you'll understand what I'm trying to say. These are all real sites that provide
immense value all being used to intelligently boost the rankings for other business sites the parent company owns.
And it works super, super well. Obviously you won't be able to replicate their success (since you need $$$$) but even copying their strategy on a smaller scale can prove very effective (which is what I've explained above).
If you want to play the long term game then you should absolutely ensure the sites are natural. By this, I don't mean slapping on a few widgets in the sidebar just to make things pretty. I mean actually spending time creating these into legitimate properties. Not to mention adding multiple links in each article - not just to the money site. We add various authority links, always mixing it up where possible and never making it suspicious. As I said, we treat these like real sites.
PBN's can last as long as your money sites if you do it correctly. The issue is.. not many people know how to do it correctly.
I've seen first hand other SEO's doing exactly this. Setting up real money sites as their PBN. The results they've been able to achieve are just silly. We're talking #1 across the board for various keywords each with 1M+ monthly search volumes...
I've seen the above strategy be used on service sites in the SMM niche which bring in $350k+ per month revenue.
Massive sites.
I've even done similar strategies for some of my clients... and their sites now make mid 6 figures a month in revenue. You read that right.
Mid 6 figures a month. @Nargil would know what I'm talking about since he helped with the initial domains for the multiple networks we created for this client.
Would this strategy be worth doing for a site that can only really make $1-2k/month? Probably not. But...
Back to my original point, it all depends on your requirements. If you have the money and you know your niche isn't "churn/burn" then investing in your PBN could be one of the best things you do when it comes to SEO for your site. If you know your niche can make
big money, then this is something I'd definitely suggest you do.