When things are close together it is more convenient. We can get more things done in a given amount of time. That is a large part of why we visit malls. Beyond the fact that people like to visit malls and generate good traffic, the mall also offers businesses other advantages too. People in a mall go in to find one item, notice others, and often make impulse purchases.
People also go to the mall to have a variety of things to look at.
We call it window shopping and we buy a lot of things when we do it. Most small businesses, and many large, ones don't own the buildings they use as their storefront. I.businesses within the mall obtain the building maintenance and other support services through the building manager and their staff. That lets them avoid the technical details and concentrate on their true business. All businesses hosted with OfficeOnWeb as a virtual domain obtain free listings in the various malls and offices we operate.