[crabbone]

> I'm sure click has its advantage if your CLI is particularly complex

None whatsoever. Argsparse is better all around. Click is just a worthless piece of software that nobody should be using.

As for the order of options / arguments. I think, the reason is the historical implementations and use of getopt that would be used in a switch inside a loop, which (maybe unintentionally) made the order irrelevant. It's likely that other libraries implement parsers in the way that is sensitive to the order. Whether that's deliberate it's hard to tell. There are definitely advantages to this approach too, but it's hard to know whether authors sought out those advantages deliberately.

For instance, when options can take arguments (especially when they can take multiple arguments) they can be confused with sub-commands or the arguments to commands. Imposing ordering restrictions helps to resolve ambiguities as to what argument is being processed. On the other hand, you may claim that not imposing ordering on arguments prevents CLI authors from creating confusing interfaces where users can accidentally mix arguments to options with sub-commands or arguments to commands.