But obviously you can probably safely pin bubblewrap to a given version, and you don't need to "install packages through it", which is the main weakness of package managers
The comments here that point to this theoretical possibility seem to be missing the point, which is that using something like bubblewrap is an improvement over running arbitrary projects un-sandboxed, and the likelihood of such an attack is far less than the likelihood of any one of hundreds of rapidly evolving, lesser known, lesser scrutinized projects getting compromised.