The value of using beldi soap before a cream or a self-tanning product comes from the surface effect, not from the product itself. The soap contains saponified olive oil, which dissolves sweat, excess oil and impurities. On its own, that would clean the skin, but it would not change the surface texture. The exfoliating component appears when you pair the soap with a washcloth or a bath glove: the soft soap loosens residue on the surface, and the cloth lifts it away. The result, according to the product information, is that skin often feels smoother after use and body products applied afterwards spread more easily.
For body cream, the practical benefit is simple: a smoother surface means the cream glides better and does not gather on rough patches. For self-tanning products, an even surface matters even more, because a tanning formula can develop unevenly on areas with excess buildup. The product information specifically mentions preparing the skin before applying body cream or self-tanning products, so this is an intended use.
Rough areas such as elbows and knees are worth paying attention to in this routine. They tend to have more buildup and can make cream and tanning products look patchy. A gentle beldi soap massage there, followed by the glove or cloth, helps level the surface. As always, keep the product away from the eyes and skip any irritated skin; if this is your first time with an exfoliating cleanser, use light pressure and see how your skin responds before using it as part of your pre-cream routine.