Itīs true that this kind of all out weapons practise is good for developing a strong, immoveable and pliant center for both Uketachi and Uchitachi. Afterall hitting two pieces of wood against eachother at full force is more constructive than smashing your trainingpartners spine into the matt at full speed.
But basic suburi and basic partnerpractise skills have to be mastered before going all out in weapons. Othervise it would lead to injury- were not talking about kendo, we are talking about weapons practise with no body protection against a heavy oak weapon with no tsuba.
So timing, blending (awase) and correct maai becomes quite important- because you donīt want to get hit
in the first place- just like when you are dealing with a real (sharp) weapon.