I take it you did not play during the first season then.
During season 1 CV was an absolute staple for every supports because the CD was short enough to use it at the beginning of the game (see who's going where, see if they rushed to an invade, etc), where the jungler started, then when you arrived in bot lane you could toss it between the two bushes and see if someone was waiting in there for the lvl 1 cheese.
The CD was short enough and the jungle routes predictable enough that good supports could literally make a jungler's life hell because they'd follow you around with the magical eye and open opportunities for counter jungle and/or kill gank potential.
CV was nerfed to oblivion in pre-season 2 and was never really seen since (ADC who were going flash + exhaust in S1 switched to flash + ignite while the support became the designated exhaust carrier - since then ADC have switched to flash + defensive spell, aka heal or barrier depending on which one is currently strongest, and the support has always packed their combat summoner spell of choice between exhaust and ignite).
I used to really, really love CV and even used it to be a complete bitch to the enemy by denying them the cover of bushes cross-map so they wouldn't juke my team (then my team was like "OH WOW!!" and I cried because it didn't give me assist gold), or bot lane so the enemy couldn't duke into a bush to avoid minion aggro after a poke. However, it has simply lost its place in the game with bot lanes being so fight-oriented and the ADC packing only defensive spells. The birth of the blue trinket simply was the nail in the coffin.