"Root" gives you administrative level access to edit, install and configure all of the files on your server, including system-critical files. It gives you ultimate access to your server. This gives you the ability to configure your server to your exact needs. While root access gives you full control of your server, it is intended for experienced users, engineers and developers. That's because you do have the potential to misconfigure or delete those system critial files if you're unfamiliar or inexperienced with what you're doing.
Yes, it’s secure. VPS security comes from each instance’s isolation from the other environments on the server. Contrast that with shared hosting, where environments are sharing the same resources and can be affected by each other’s vulnerabilities. A denial of service attack on a website in a shared environment can bring down other companies’ data and websites hosted on that server, where each VPS environment is isolated and protected.
When smartphones took over in the early 2000s, data usage and cellphone bills went through the roof for many families — mine included. My family’s shared data plan wasn’t perfect — some months, someone would rack up data usage and leave the rest of us strapped — but it allowed each person to pay a lot less per month than if we each had an unlimited data plan.
The great news for VPS customers these days is that most web hosting companies offer managed VPS hosting. Here, not only will they set up your server environment, but they’ll also take care of tasks such as software upgrades, security patches, etc. Also, provision time is now greatly reduced and you can be up and running with your VPS hosting much more quickly.