it seems to me that what sets the junins apart is the fact they have students

i think its a choice of the village elders saying wow kick ass guy your a junin


considering the village elders also decide who is a chuunin they just do it as a big event because kids like attention and its a way to show off there up comeing ninjas and there skills cause of the money,

but it comes down to that old people pick who passes... wonder what the pre req is to becomeing village elder

i guess live in the assination buisness to an old age