vim-ripgrep is a wrapper around the ripgrep (rg) file searcher tool (an alternative to grep).
Integrating a searching tool like ripgrep doesn't necessarily require a plugin. Vim provides configuration options to configure the :grep command so it calls a different shell tool than the actual grep one. Check :help 'grepprg' to know more. This plugin provides an alternative :Rg <patter> that can result in a nicer user experience since the results are piped directly into the Quickfix window without the shell executing the command showing up or the screen flickering. It also supports some configuration options described in its README file.
vim-ripgrep doesn't have any incompatibility with Vem and doesn't require any special configuration to work with it.