Brand and Logos are interlinked or can say logo is the brand, and for brand logo is must. The question arises here, why logo and not any design of physical product is considered, reason being brand covers several products and it is not necessarily important that brand is only one product, but yes many products can come under one brand. So for the reason, it is important brand to be some wider aspect design other than design of any physical product.
As brand grows, the logo embeds into the mind of the customers, slowly and gradually logo becomes the identity of any business or brand. Most of the Industries and companies are very possessive about their logos and they avoid doing any changes into their logo until and unless it is very urgent.
In almost all advertisements, we can see the logo with the brand. Logo is the biggest marketing strategy and business invests a lot to get best out of it.