You can, but since we offer real user monitoring, it won't yield many insightful results. Considering that only those who have access to your staging area will go there. And they frequently use your team's or your own internet on desktop computers. Therefore, we wouldn't advise doing this.
We won't stop you if you decide to include staging with your domain subscription. Installing the snippet on your staging site only requires making sure that your subscription allows you to add this extra domain (for example, eCommerce comes with 2 domains by default, but you can add-on extra domains).