Three ways to identify someone
Access control always works on the same principle — a reader checks a credential and opens the door or doesn't — but the credential itself can be a card (RFID, Radio-Frequency Identification), a fingerprint (biometrics), or a phone over NFC (Near-Field Communication). Each of these three options has its own most common failure mode, and that failure mode should drive the choice more than the per-user cost does.
Card: quick to issue, just as quick to lend
An RFID card is cheap to issue and replace — a lost card gets deactivated and swapped in a couple of minutes, with no need to re-enrol anyone physically. The weak point is exactly that ease: a card can be lent to a colleague who forgot theirs, which for time-attendance purposes directly raises the question of whether the card was actually with the person whose presence got logged.
Fingerprint: can't be lent, but has its own limits
A biometric fingerprint solves exactly that problem — it can't be borrowed or left at home. The limit is physical: a wet, dirty or gloved hand often won't read reliably, and some staff have reservations about biometric data collection in the first place, which is worth addressing before rollout, not after.
NFC phone: always at hand, until the battery isn't
An NFC phone credential uses a device people already carry, and access can be revoked remotely and quickly — just remove the credential from the account, no physical collection needed. The weakness is just as practical: a dead battery or a phone left at home means no identification at all, and a visitor without a compatible phone has no way to register on that channel in the first place.
Recommendation: combine by door, not across the whole site
Choosing one option for the entire site is rarely the right call. A card at the main entrance where speed of issuing matters, a fingerprint at the server room or the till where identity has to be beyond doubt, an NFC phone as a backup or visitor credential — that combination covers each weakness exactly where it matters most. Door-by-door layout and integration with time-attendance are worked out on the access control page.