BB cream is short for 'blemish balm' cream. It's a versatile combination of products such as moisturizer, primer, SPF, foundation, skin treatment, and concealer. It was originally developed in Germany as an all-in-1 cream to be used by patient's post-laser treatment for protection, coverage, and hydration.
You can use a BB cream as part of your daily routine in place of foundation. If your skin tends to be oily, the moisturizer in a BB cream may be enough. But if you have normal or dry skin, you may want to apply a moisturizer before your BB cream.
From a skincare product perspective, BB cream is better than foundation since it's packed with ingredients that can nourish and moisturize your skin, as well as cover over it. If you want something that gives light coverage that makes your skin appear more natural, BB cream is also better than most foundations