The reason that it’s required to install wine-staging is explained as being related to dependencies:
Although Lutris provides a wide variety of Wine builds having a recent version installed system-wide provides additional dependencies. Some of these dependencies cannot be provided by the Lutris runtime.
There seems to be an insistence that the version of wine to be installed must be wine-staging rather than wine-stable or wine-development. Assuming dependencies is the only reason to install wine system-wide (Lutris can manage the specific version of wine used for games independently of what’s installed system-wide), there would only be a reason to pick wine-staging if wine-staging results in different dependencies being installed, compared to wine-development or wine-stable.
Are there other reasons than dependencies for installing wine-staging specifically system-wide?
Is there a dependency difference between wine-staging and wine-development?