Often, virtualization technology is not required to emulate x86 or x86-64 instructions, albeit at the expense of speed. As a best practice, I would leave it explicitly disabled unless required. while it is true you should not enable VT unless you really use it, there is no more risk if the feature is on or not.

Is Intel virtualization technology safe?

Yes, it's safe to use a feature that your CPU provides and no it won't cause overheating or void the warranty. It exists to make virtual machines like you're creating work better/faster.

What does Intel virtualization technology do?

Intel Virtualization Technology (Intel VT or IVT) is a capability provided in Intel processors that enables multiple operating systems and environments to consolidate and host on a single processor. ... Intel virtualization technology was formerly known as Vanderpool.