Keyless access control replaces the mechanical key with a code, card, fob, phone or biometric. It still uses a credential; the key is simply not a piece of cut metal. The gain is that access can be revoked, scheduled and logged without rekeying a building.
Keyless describes the user experience, not the security level. A shared code can be weaker than a key, and a modern smart card much stronger.
Codes are the weakest option
A four-digit code is easily observed and shared, and it leaves no record of who entered. Use codes as a secondary method or alongside a card.
Battery locks and wired locks
Standalone keyless locks are quick to fit but need a battery and audit plan. Wired locks on a controller cost more to install and give central control and logs.