WP Statistics doesn’t officially support multi-site however it does have limited functionally associated with it and should function without issue. However no support is provided at this time.
Version 8.8 is the first release that should install, upgrade and remove correctly on mutli-site as well as have some very basic support for the network admin menu. This should not be taken as an indication that WP Statistics fully support for multi-site, but only as a very preliminary first step.