Lion = 6 rapiers so when you stun and hex you can wtfpwn
BM = 6 rapiers so when you ult stun you can wtfpwn
Veno = 6 rapiers so...something...wtfpwn
But really, Phase is great for many int heroes early due to the armor, though its been nerfed. The phase is useful in many situations as well. Lion is incredibly item independent, only needing survivability. In competitive games, this is one reason why he's an excellent support character - item independent which frees up farm for carries, and also gives him money for wards, stun+hex for control, and finger to set up kills for your carry. You should generally never be farming enough for travels, and certainly not for Guinsoo. You shouldn't be farming at all really, a good Lion will be all around the map to set up kills, killing things along the way only as needed.
That said, this is obviously for a pub, in which case I don't understand why people ask for item builds. ANYTHING works in pubs. If you want to be a DPS Lion, grab scepter, guinsoo, travels, Dagon, whatever. Trying to ward or support in a pub will only make you want to kill yourself.