Sharing is a form of advertising. If you want to promote a company or product there is no better way then sharing.
I remember seeing a video where a company exec said that they want to sell there product but they also wanted everyone to be using there pirated copy vs another company's application.
Most people won't pirate because it involves work. The people who do sometimes are the trend setters who can encourage others to buy.
In some countries there are exceptions to copyright for non-software that allow making copies for use of friends.