Take the two-way marine refrigerators, for example.
The compressor motor is actaully AC and are either 24 vac, 28 vac or sometimes 32 vac.
When on 12 vdc, an inverter provides the ac voltage..... and when on S/P, a step-down transformer provides the ac voltage.
The vac motor is apparently used due to greater efficiency, and definitely for a more stable rpm.
Perhaps this little air conditioner unit does similar. I don't know!
I agree on the risks of using of the Honda EU units, but will tell you that many people are using them, and doing so safely.
It's like many things.... ya gots to be smart about it!
.