To be visible.
To be credible.
To be profitable.
It's way more than just a logo.
Branding is what clients expect, experience and remember about your business.
In doing so correctly, you target your ideal client. (Provided you have a super-savvy design agency behind you, of course). This means attracting the work, clients and staff that you want.
By NOT having a strong brand identity, how many opportunities will you be missing out on? Your competitor is doing it after all...