Exfoliation (known biologically as desquamation) is a normal feature (activity) of the skin surface (superficial dead and keratinised cells of the outermost horny layer).
It is the process of shedding worn out horny cells in the form of invisible scales (collections of small numbers of cells).

Products (e.g. creams) and treatments associated with it, together with its abnormalities (due to disease) can be said to constitute another set of bodily ambiguities.

[Note:
Disease aspects will only be mentioned in passing].

The skin (as a whole) is the ultimate barrier and connection between the body and the environment.

Its ability to protect against the entry by many harmful environmental agents (including microbes) depends to a great deal on the chemical composition and physical construction (nature) of its very surface (made of the outermost cells of the horny layer of the epidermis).

[Note:
Various substances (produced mostly by the epidermis itself) help the cells of the horny (outermost and dead) layer of the epidermis to carry out some of their barrier functions].

The skin surface is best described as transient because the cells of which it is made are continuously being shed (desquamated or exfoliated) and replaced. Such a constantly ‘renewed’ surface offers the best possible protection to the rest of the skin (including the deeper living layers of the epidermis) and the body as a whole.

[Note:
1) There are limitations to the protection a thin layer of biological materials which constitutes the skin surface (outermost rows of the horny layer) can offer.
2) Nevertheless it has kept human kind in existence for a long time!].

Cells migrate from the layers immediately below to take the place of those (‘worn out’ ones) that are desquamated (exfoliated in everyday language).

The cells that move upwards (or outwards) from row to row until they are exfoliated all originate from the deepest layer of the epidermis which is called the basal layer.

[Note:
1) During the migration from the basal layer to the horny layer each epidermal cell undergoes differentiation (over about 14 days) which changes it from a soft and living structure to a dead and toughened (keratinised) one.
2) Horny cells spend about another 14 days in their 'dedicated' layer and then are desquamated (exfoliated)].
3) Skin scales make up most of ordinary household dust.

Shedding of visible scales (collections of larger numbers of horny cells) is abnormal. This can occur in infectious conditions (e.g. ring worm) and non-infectious conditions (e.g. sunburn, eczema, psoriasis, etc.)].

Additional to the normal desquamation that follows epidermal cell differentiation (and migration) is the desquamation that is facilitated (accelerated) by routine skin-centred activities. These include washing, shaving, make-up application and removal, etc. Friction against clothing, bedding, etc. has the same effect.

Thus for the normal (healthy) skin, treatments and products designed or aimed specifically to bring it about (exfoliation) could be said to be unnecessary and perhaps in some cases excessive.

Note of Caution:
Excessive exfoliation can have detrimental effects in the long run, especially if epidermal differentiation and replacement cannot keep pace with it.
A good example of ‘swings and roundabouts’, I would be inclined to say!