The ones I fired had a pretty heavy bolt. I’m guessing that it had a mass of at least 400 grains.... you know, like a small 45-70 projectile, or a large 45 ACP round.
Sure, at 1/3 the speed, but remember, they come with broad heads too.
Laugh all you want, but weather or not it’s legal is not the debate.... it WILL kill.
If you’d like to give your kid a toy like this, you might want to consider not giving her the broad heads... however, she is probably slightly smarter than her dad, so she may have the skill of logical deduction on her side.