Vulkano follows the Rust definition of safety. It should be impossible for the user to get any undefined behavior using safe code, even when that code seems absurd.
The actual Vulkan functions called by vulkano are precisely documented, making vulkano very easy to profile or debug with Vulkan tools.
Vulkano tries to have as little runtime overhead as possible by moving some elements to compile-time, while still maintaining safety.
Vulkano provides convenient methods on top of Vulkan making it faster to develop with. You can focus on the graphics.