Activated charcoal has a highly porous structure. In this shaving foam, that porosity allows the charcoal to bind impurities and excess residue on the surface of the skin. During shaving, this creates a light cleansing effect — the charcoal helps lift surface dirt and oil as the foam is spread and rinsed away. It is not a scrub, so it does not physically exfoliate or polish the skin.
In a shaving foam, the charcoal is combined with the foam's main job: preparing the beard. The dense, creamy layer softens the beard hair, which lets the razor move more evenly and may reduce the feeling of friction between blade and skin. The charcoal does not make the blade sharper or change your hair thickness. Instead, it supports a cleaner finish after rinsing.
For a normal-skin shaving routine, this can be a useful single-step product: shave preparation plus surface cleansing. Because the foam spreads quickly and rinses off easily, it does not tend to leave a heavy or greasy residue behind. If you already use a separate face wash before shaving, the foam's cleansing effect is extra rather than a replacement.