What is a brand? For some, a brand is the prettied-up exterior of an organization that gives it appeal (one hopes). For others, and we include ourselves here, a brand is the idea of an organization that people carry in their minds. It's a concept.
The idea is formed as a composite of all things associated with the business: product, positioning, company type and size, history, location, vision, etc. Looks are here too, but they certainly aren't alone. And they shouldn't contradict the rest. A bold, cutting-edge visual identity will feel wrong layered over a company that is neither bold nor cutting-edge (not all have to be).
When "brand" is understood this way it becomes almost synonymous with "business." A brand may appear plain, but this could be intentional because the company offers a no-frills experience, is more straightforward to use, and is cheaper than its competitors. That is brand. On the flip side, a luxury retailer that doesn't scream lux might cause potential buyers to wonder if they really are getting extra for their bucks.
What we're narrowing in on is the value of consistency and authenticity to a successful brand and business. Branding is much more an exercise of knowing your business and fixing a clear position in the minds of customers than of painting the exterior. This isn't meant to devalue the finishing work, because it matters immensely. It's to argue that the finishing work of a brand is not a papering over of what's behind it but an embellishment of it, and that "brand" is not just the finishing work but is everything from the finely laid trim to the foundation that was poured and set when the business first began.