Git is supposed to be a decentralized system, but all the tutorials and best practice workflows I have found on Google suggest using a server (usually GitHub, or else set up your own)
I am using git for small personal projects (2-3 people), where can I find a best practice workflow for syncing changes directly between the team members machines.
Alternatively, what are some compelling arguments for why I should avoid this and instead set up a 'central' server?
Depends on what you mean by "server". Git will work happily without a central server, although many teams find it convenient to have a central repository.
If by "server", you mean "install server software", git will also work (central repository or not) without any special software, through ssh or on the file system.
See this document for possible workflows
The workflow that many use is that all developers "push" (send) their changes to a common repository, and get all the changes from that repository. Something like this:
In this case the central repository can be on one of the Developers computers, on github, or any other place
You can also use git without any server, just using email. In this case the flow would be like this:
This can even be done in a semi-automated way
You can setup git to use more than one "remote" repository. The caveat is that you should never push to a repository that is checked out (that is, a Developer copy on which someone is working). So in this case the flow would be like this:
IMHO this type of workflow will quickly lead to confusion and breakdown.