The big problem with this is that your data set no longer represents your live data.
A staging server needs to be representative of live, otherwise you can’t test everything prior to going to production with whatever changes are planned.
I’ve spectated some pretty impressive failures where non-representative tests failed to identify issues which later arose in the live environment. More often than not they occurred because of data quality issues.
Double-barreled surnames (with and without the hyphen) and accented characters for example caused tremendous amounts of hurt.
If it’s a true staging server then it needs to mimic live precisely. The copy doesn’t need to be visible to normal users and disabling non-staff email is pretty advisable, but otherwise it’s just inviting problems.