Hello, it has been voted on https://fr.wikibooks.org/wiki/Wikilivres:Le_Bistro/2021#Pour_autoriser_tous_les_inscrits to change the right to use [[special:upload]], from administrators only to any registered user.
The only reason for enabling local file uploads, is to upload non-free uploads. According to https://foundation.wikimedia.org/wiki/Resolution:Licensing_policy an Exemption Doctrine Policy (EDP) is necessary for this. I don't see an EDP approved an listed at https://meta.wikimedia.org/wiki/Non-free_content#Exemption_Doctrine_Policy.
unfortunately, https://fr.wikibooks.org/wiki/Cat%C3%A9gorie:Images_en_fair_use is not a document that can be accepted as an EDP. According to the WMF Board policy https://foundation.wikimedia.org/wiki/Resolution:Licensing_policy, an EDP needs to be a policy (ie. a policy formally adopted by a project) that defines which copyrighted images may be used on the project, in a way that abides by both the US law and the law of the country the project is predominantly accessed from.
The category you linked currently has a list of templates, but that list is merely informative, not policy-making. In another words, it would be acceptable for any community member to update that list, while the same would not be the case for an EDP (as that is a policy).
Could you please write a formal policy and link it here, please? Thanks a lot.