Everything about the mission provided valuable data: especially that damaged blade. Failure modes are useful. Next, it might be useful to try flying anyway.
If not, they still have running cameras, sensors and computer, until Perseverance moves out of range.
The rotors will be unbalanced (even if the other side also broke off, chances of the same amount breaking of are as remote as the thing itself), so it will vibrate and probably tip over if it spins too hard