There is a big difference between feeling rugged when wearing Levi’s jeans and expressing the strong, rugged side of you by wearing them. The differences between the two can be important.
Brands essentially deal with different kinds of benefits. An identity that is based on intangible associations or brand personalities provides the brand with more strategic scope and gives you more liberty to extend the brand.
On the other hand, a brand that relies on the superior performance of a key attribute will eventually get beaten by competition, because the attribute is a fixed target for competitors. The result can be a loss of differentiation, or worse an inferior position on an attribute that is associated with the brand.