The importance of building a brand is rooted in human evolution. A lot of energy is consumed by our brain working, which is why we only use our brain when we really need to.
You may not realise it, but in your daily routine you make many decisions automatically, without thinking. This is no different in shopping situations either. When this happens, you choose brands that have been able to make themselves more visible to you than the others. Due to branding, the design is familiar to you, that’s why you feel trust, that’s why you consider it authentic.