If you have a business entity that you run the business under -- then use what you have in place already... But maybe then you want to "trademark" the new brand and just "do business as" to save time, cost, hassle.
BUT one of the main reasons for incorporation is about liability and such, given your shoes and worn and could be subject to liability or other injuries -- you want the corporation to shelter you from legal action that would hold you personally accountable (another reason to not use your "name" as well).
So there is accounting, banking, and taxation reasons,
also legal protection reasons for incorporating,
and last there is the allocation of equity if you take any investment...
-- next is the different versions S Corp, LLC, etc... but that's another topic.