If it ‘works’, then why can’t they build their own ship?.................🙄
“Works” in what sense?
Ion drives have already been used for powering spacecraft. They work by generating a small amount of thrust for a very long time. They’re great for driving spacecraft around the solar system, useless for lifting the spacecraft into orbit. SpaceX and RocketLab are really good at putting things in orbit; no need for these guys to reinvent the launch vehicle.