Virtual environments are not just for conflicting requirements. I write code for clients on my laptop and don't want to clog up my packages directory with project specific libraries that I'll never use myself. Once the project is done and I turn code over to a client, I can delete the virtual env and all the installed libraries. Virtual envs also allow me to have multiple versions of Python installed on my machine.

This discussion is a lot like version control. How many people made daily (hourly) duplicates of project folders before learning the benefits of version control?