Yes expensive, but I think this will become a great sport. May be not as exciting as using wind or waves for foiling, but a perfect alternative for days without wind and waves. And of course for people who do not live at the sea.
There are also e foil boards available. I found this comparison: https://e-surfer.com/en/electric-hydrofoil-comparison-e-foil-overview/
They are a little bit pricy, but still cool stuff.