Re: BB and CC creams[ Edited ]
BB creams cover the ground of being known as "beauty balms" or "blemish balms" while CC creams cover the ground of being "color correcting" balms.
BB creams and CC creams serve to be multi-functional formulas, helping to prime/prep skin, protect (infused with SPF levels), perfect, correct, and moisturize skin.
BBs specifically are more so infused with oil-control abilities or blemish fighting ingredients, helping to target minor skin care woes. CCs are infused with gentle brightening ingredients such as vitamin C, licorice, or arbutin to help color correct discoloration caused by age/sun spots or post acne marks.
Though these products do cover a lot of ground, in terms of coverage and how they wear they fall in between tinted moisturizers and actual foundations. They'll give more coverage than thinner/lighter weight TMs, but they don't cover as much as an actual foundation itself. And though they tote priming and moisturizing benefits, actually using a moisturizer underneath and primer is and can still be suggested to ensure even better wear (especially if issues on skin such as dry/flaky spots or enlarged pores are something to deal with as primers form more of a barrier over skin than the BB/CC itself). Moisturizers are and can still be recommended due to the fact that BB/CC creams are more of a make up/skin care item hybrid so its focus won't be solely on moisturizing/skin care.
In a pinch or on simple days, skipping moisturizer or primer in lieu of a BB or CC cream is fine, but there's definitely a lot that can be played with depending on your skin type and formula chosed.
BB/CC creams may or may not also cover and conceal all that is needed. If someone is suffering from heavy redness for example, they may still require either a color neutralizing primer or a bit of concealer along with their BB/CC wear. If you're interested in BB or CC creams check out the below link. At the top will be more info along with showing top picks and recommendations for BB and CC creams carried by Sephora depending on specifics such as "bests" for shine control, sensitive skin, deeper hydration, and anti-aging,