I've used it, but not recently. It was always a novelty to connect an actual Wii controller with bluetooth, set up some LEDs for motion tracking, and play Wii on my laptop.
As for performance: Using software to implement behavior equivalent to specific hardware is almost inherently inefficient. JIT-style processing of the opcodes helps, but you're still going to use multiple operations on the host CPU for each one that you execute from the guest code. Plus emulation of device synchronization that would've originally been done in hardware and that don't have direct equivalents on the host hardware.
As for performance: Using software to implement behavior equivalent to specific hardware is almost inherently inefficient. JIT-style processing of the opcodes helps, but you're still going to use multiple operations on the host CPU for each one that you execute from the guest code. Plus emulation of device synchronization that would've originally been done in hardware and that don't have direct equivalents on the host hardware.