If you need one, buy one.
I don’t see any practical, technical, ethical reason to include one. I see environmental and simplicity reasons to not include one.
The means by which people will bend over backwards to paint Apple in a good light is insane.
But yeah drop the user guide too and put it on a website, good idea. The box, not that because it protects the product leading to less wastage.
As for those missing chargers, they probably have multiple reasons for not including them. The environmental impact may even play a small role. Ultimately though, the main reasons are going to be business driven (e.g. reduced manufacturing costs and perhaps increased sales of chargers). If these people were truly interested in protecting the environment, they wouldn't be in the business of selling disposable consumer goods.
If people are going to buy consumer goods anyone trying to make it a bit better should be celebrated.