That is why you would do it with a house with strong diplomatic ties, it is viable trade wise increase trade and military aid if a war broke out e.g if liberty were to be allies with bretonian they could send vessels over to bretonia to assist with the Kusari mess. Rp wise could rp the diplomatics, it could be the ultimate trade agreement, or declaration of friendship, really save on the long time it takes to get across the systems, and it would show the pinnacle in advance jumpgate technology.
([aimed at the warcomment] i dont think someone would declare war on someone they are friends with ya wouldnt build this in the first place if ya werent friends and were just gonna end up declaring war on the other faction)