It depends what you do with such bikes. My son at 5 y.o. rode green trails in a bike park with a woom bike (not a balance bike), and I have seen other dads bring kids with balance bikes to bike parks.
If that is your objective you are ok to spend a few hundred dollars on a kid bike if that gives you the hope you will be saving a lot more than that from the dentist.
This said, a dad like me whose passion are expensive bikes, is very likely to be willing to spend a few hundreds on a kids bike, especially if you have more than one kid and you plan to pass the bike to the other son when the elder one outgrows it.