What are ceramides? To learn more about them, see this post.
Here are the essentials. Ceramides, chemically, are a very distinct type of lipid (fat). They fulfill different functions. The easy one: they work as “cement” as part of the epidermal barrier. You need these ceramides. They are made by your own skin, using lipids already present in the cells. One way of preventing their loss is to provide lipids tyo your skin so that it can keep making them. Another is not to eliminate by eroding your epidermis with acid peels and abrasion.
The other aspect of the question. Do you need ceramides in your skin care products? No. They will not integrate to your skin. They may help by giving some temporary reinforcement to the skin barrier. But, for this purpose, it can be replaced by many different lipids.
The reason why you find ceramides in many skin care products is for “label value”. You may know enough to know that ceramides are important but not enough to know why and where.
You will find ceramides in some Skin Actives products. But also, and more importantly, you will find fatty acids that will help your skin makes its own ceramides, coontributing to your skin health (and beauty!).