Really doesn't matter if the tube stands up to the vacuum or not, main thing is that it doesn't leak. Balancing effect is negligable, will only slightly help at minute throttle openings anyway.
The factory probably didn't trust 750 owners to replace a plug on the balancing stubs, hence the hose which is far more apparent. After finding out what a pita is was to fiddle out the blanking screws and to fit the stubs to the triples, they did that themselves and connected them with a hose. Nice solution but hose condition is critical in both cases!
piet