The linked paper makes it clear it will be released under a non-commercial license. You will download it gratis (so it won't be paid), but it won't be open source.
So they make a more available alternative, but they maintain control over it, and in turn gain control over the people and companies using it. Similar to what Microsoft did by bundling Windows with PCs[1].
I already have a multitude of ideas on potential nefarious plans based on this, but I'll keep them to myself.
[1]: Sure they got a licence payment, but since it was built into the price and non-optional, it was effectively equivalent to free from the customer POV. It effectively became a tax. I have to admit, Gates might not be a genius programmer but he sure knows how to design dark patterns :)
It's pretty simple. GPT models are essentially information weapons. People are going to get their hands on them, so might as well give them a model where you can identify content generated with them, so you can know who is using them for nefarious purposes. Like how many printers encode hidden patterns on paper that identify the model of the printer and other information[0]
I'm not saying that Meta did it, but recent research shows that it is possible and hard to detect - https://arxiv.org/abs/2204.06974 - so if they really wanted to, they could.
By training a GAN. A trained GAN will be able to accurately guess whether a block of text was produced by this GPT model, some other GPT model, or is authentic.
https://petervojtek.github.io/diy/2015/05/19/countries-with-...