Another benefit of virtualizing servers is that they are no longer tied to a hardware platform. This provides the ability to virtually expand or upgrade (upgrade) the hardware platform during operation without significant downtime (~ 1 second downtime). Also, a hardware problem does not result in longer downtime (assuming existing spare capacity) because the VPS can be restarted quickly on a different hardware.

The web and server hosting world is full of abbreviations that look as though they were designed to confuse inexperienced hosting clients: IaaS, PaaS, SSD, SSL, VPN, VPS, and many more. It’s especially confusing when abbreviations are similar, but mean completely different things, as is the case with VPN and VPS. I’ve often heard hosting clients say VPN when they mean VPS, and vice versa.
The force driving server virtualization is similar to that which led to the development of time-sharing and multiprogramming in the past. Although the resources are still shared, as under the time-sharing model, virtualization provides a higher level of security, dependent on the type of virtualization used, as the individual virtual servers are mostly isolated from each other and may run their own full-fledged operating system which can be independently rebooted as a virtual instance.