A key safe is a secure box that stores a physical key, accessed with a PIN code. You must manually change the code between guests. A smart lock replaces the physical lock entirely and generates unique, time-limited codes per guest automatically. Smart locks offer remote management, audit trails, and property management system integration. Key safes are cheaper and have no tech dependency. For a single property with low turnover, a key safe is a practical option. For higher turnover or multiple properties, a smart lock saves significant time and reduces security risk.