It is however an extremely important step. Once your business is registered, you have an officially registered business name and registration or tax file number (this differs from country to country). With these registration details you can now contact wholesalers and distributors.
Reputable distributors, wholesalers and manufacturers will ONLY deal with you, if you are a registered trader or put the other way round: Anyone willing to sell you wholesale goods without verifying that you are a registered trader is most likely not reputable and probably not offering you wholesale prices.