I'm 15 so I wouldn't know about buying my kids anything, but all those cars you listed are reputable brands, which also are required to meet certain safety standards. The bikes are not only heavy and crappy, but also unsafe in many situations. Kids use a lot of things they aren't intended for and would have no problem taking their bike which is "not suitable for offroad use" off road and maybe try jumping it, that is when they are even more dangerous. Also, the crappier something is, the more discouraging it is to use it.