Well there is "safe" and then there is "safer"!
Older electrical systems were basically safe. But newer electrical systems are safer.
The difference is if there is an electrical malfunction. Like if a wire comes loose. Or someone drills a hole in a wall and this causes a wire to break.
Newer electrical systems take this into account and are designed to be safe even if these malfunctions occur.
So basically safe? Yes so long as no wires become disconnected.
Could it be safer? Yes, a separate ground, non-bonded neutral bar, and separate ground wire run to the main panel would be safer.