It's a common misconception that you can 'grind' the gears in a modern gearbox, you can't. Unless you're driving a 18 speed truck or a British sports car from the 1960's your gears are in constant mesh, all of them. (except reverse)

It boils down like this. Every gear is constantly meshed with it's partner but one half can slip on the shaft it's running on. Whether it be dog or synchro engagement is just the way you lock that gear to the shaft, thus driving through that gear while the rest just idle away free. Has nothing to do with being straight, helical, spur, herringbone or whatever shaped tooth.

Dog boxes are not stronger because they are dog engaged, that just means they shift faster. The downside is the driver has no help in synchronising the process, he must do it himself.

I know a few guys that use dog boxes in road cars and they all have one thing in common. They spend more time off the road than on it.