A discreet but very present instinct for vigilance
Even the calmest cats retain a protective instinct. Some feel the need to “watch over” their human while they sleep. By positioning themselves near your face, they remain attentive to your movements and breathing. This behavior is more common in cats who are very attached or naturally vigilant. Without being in a state of alert, they adopt a reassuring presence, as if to say, “Everything is fine, I’m here.”
The simple search for warmth and comfort

Sometimes the explanation is the most obvious… and the most endearing. Your face radiates a gentle, consistent warmth, ideal for a cat seeking comfort. In winter, or in a cool room, snuggling up to you is a simple way for them to feel good. It’s comparable to curling up under a soft blanket, with the added bonus of your familiar scent.
A habit inherited from his childhood

Some behaviors develop very early. A cat that has grown up surrounded by other cats, or very close to humans from its first weeks, may have learned that the face is a natural area for interaction. In this case, there isn’t necessarily a deeper message to interpret: it’s a reassuring, long-established habit that it reproduces spontaneously.