Carob (Ceratonia siliqua L.) is used in foods through chemically and technologically distinct fractions, including pulp flour or powder, roasted powder, syrup/molasses, phenolic-rich extracts, seed germ flour, and locust bean gum. This narrative review critically evaluates when these ingredients provide reproducible advantages in bakery, confectionery, pasta, beverage, meat, and dairy systems. Rather than treating all carob-derived materials as a single ingredient, the evidence is organized according to fraction, processing history, inclusion level, food matrix, technological function, sensory consequence, and level of biological evidence. Food-matrix studies consistently support several technological uses: fibre and polyphenol enrichment of cereal products; partial cocoa or sugar replacement where flavour and colour are acceptable; hydrocolloid-mediated texture control by locust bean gum; and valorization of molasses pulp or seed-derived fractions in fibre- and protein-enriched formulations. However, optimum inclusion levels are strongly matrix-dependent, and higher substitution can impair texture, flavour, colour, or processability. Roasting, drying, extraction, fermentation, baking, storage, and gastrointestinal digestion modify phenolic profiles and functional responses, making direct comparison among studies difficult. Evidence for antioxidant, antimicrobial, prebiotic, glycaemic, or other physiological effects is substantially stronger at the chemical, in vitro, and food-model levels than at the human clinical level. Sustainability claims are also promising but remain insufficiently quantified because life-cycle assessment, energy, water, transport, and waste-balance data are scarce. The main contribution of this review is therefore a formulation-oriented synthesis that identifies the conditions under which specific carob ingredients are technologically useful, while separating established food-function evidence from emerging biological and environmental claims.