well to start with the listing has a lot of lies in it.
It's a bog standard melted plastic extruder that says it uses abs and pla so you absolutely CANNOT draw directly onto your hands. If using abs the plastic is going to be around 220c at the point it comes out of the pen. So drawing on your hand would NOT be advisable.

If you want a child safe pen the you need to get one of the uv light cured resin pens. They use a liquid that sets hard when exposed to uv light and it is safe to draw on your hands with.

That said, I suspect this is just an advertising post anyway. But it can't hurt to point out that hot molten plastic and child's hands should never be brought into close contact.