Better than leaving your stuff out in the room, but not by much. You could get into one easily with a Sawzall. Think of a dollar amount of loss that wouldn't devastate you. Anything below that goes in the in-room safe. Everything else goes downstairs in the front desk safe.

Thefts from those safes are fairly rare though. My high-stakes gambler colleagues have collectively left tens if not hundreds of thousands in those safes without incident. Other than where they invited an untrusted person into their room for an overnight visit willingly.