This is simply getting a marketing address in one of the many Dubai business centers and using PO box and secretarial services on a monthly basis. This type of Dubai virtual office does not entitle to a residence visa or corporate bank account. It is mostly used by people or companies who just want to put the name "Dubai" as a marketing tool and address on their PR material. Such an arrangement does not entitle to legally do business in the UAE.
Without valid business license that you can either get through a business set up in one of UAE's plenty free zones or setting up with a local Emirati sponsor (LLC or professional company) you are not allowed to conduct any business in UAE. Companies who are seriously considering working with you will always ask for a valid business license. The business center type of virtual office set up will cost you from AED 450 per month onwards depending on the type and amount of services requested. This is just a virtual marketing address without physical space and no legal set up.