As you can see here, the main question is what are the advantages over Ansible, a mature and the most popular agentless configuration management tool written in Python. So I propose putting this answer right to the landing page
As you craft your "Why this and not Ansible" content, you might actually state clearly what you already noted on the Performance page, namely: "One of the reasons pyinfra was started was performance of agent-less tools at the time." If I read that, it'd instantly make me want to stick around and read some more, play with pyinfra, etc. BTW, i will be playing with it anyway, but just wanted to point out that you likely won;t need to start from scratch for copy (on a comparison or answering "Why this and not Ansible" content). Cheers!
Is very interesting though, I think I'm gonna try it myself.
One of them is handling "if-this-then-that-else-that". Being purely declarative, Ansible is horrible at that.
Pyinfra can be used in imperative mode, am I right? This would make the use of if-else a breeze, which would be a really good reason for me to to switch.
In puppet and saltstack you can declare that a folder is empty and declare a specific file in this folder. The system's smart enough to delete all the files except the one.
To achieve such feat in ansible is hard. Easiest way is to have two tasks, one deletes everything and second recreates your file. Doesn't feel very declarative
Unrelated thing, they don't even try to be declarative in ansible E.g you can have a file with state "touch". It not a state if it updates each playbook run!
ansible modules (built-in and community) are a different matter. generally, quality will vary.
I'm fairly sure that the way to make Puppet do what you suggest is the same in Puppet and Ansible. The difference is that Puppet is smart enough to not actually remove you file during every run (I think). On the other hand, Ansible will normally not be configured to run every 30 minutes like Puppet, so it's much less of an issue.
Both tools are great but they work some what differently. How you think about using them is much the same though, you need to tell the computer what to do. In Puppet this is often talked about is if you describe the state, I suppose that's partly true, but in the end you have a series of actions the computer will need to take to achieve this state.
Pulumi for Terraform and Dagger for Docker are two examples I use
I like CUE as a language to replace my Yaml that has some of the typical language constructs but maintains the declarative approach
I use ansible for creating machine images or initial provisioning. (I don't run the ansible, someone racks the host, sets it's build state to install, and boots the host and it joins the appropriate cluster and people do container things. I don't necessarily know when my ansible runs against a host.
I also have a pretty good stack of ansible playbooks that I use manually day to day for hardware validation for new server models and one off type stuff. But again, I never really know what I'm running against or have pet servers.
A good chunk of hardware validation runs automatically if the boot target is set to hw-validate, but the whole point is that you are gonna find stuff that doesn't work with your standard process and either pass on it or adjust.
I do run tf to provision cloud infra so its transparent to the devs, and, honestly, not sure how ansible is dated and tf is not, they are pretty much the same thing in a different coat.
And honestly, generating thousands of lines of conflicting generic yaml isn't really much of an improvement over writing it once and running it automatically on 1000s of boxes.