A business might want to use virtual machine to allow outside customers access to files
completely eliminate physical servers
easily secure the company intranet
remotely maintain servers

Allow outside customers to access files

Explanation:

A VM doesn't eliminate the need for additional load balancing hardware, an intranet is maintained with multiple computers typically, and remotely maintaining servers can be accomplished with SSH.

The reason you would want a VM for outside customer access is so that they can't interfere with anything outside of the sandboxed environment, this helps to mitigate hacking and easily isolate specific customer information.