BOV Bottom Nipple Question

[spadepro22]

I just installed my ngr bov and the bottom nipple is unhooked. My knockoff greddy bov that I just took off didn't even have the nipple on there for me to hook up. Question is, what are the benefits of hooking up this bottom nipple vs leaving it unhooked?

 

[FIBA M - EC17PSE]

Ive got mine capped and its not doing any harm and some also say leave it open.

 

[RadDsm]

Leave it open.

 

[blkgst97]

You can hook it up to a boost source to be more fast acting, down side is it wont be able to hold as much boost.