It depends if they frequent your area, they appear in my living room twice a week...so I wouldn't "invest" anything in one. I guess I have 3 about 1600cp and 120 candies, they seem slow and not that powerful. I will say just take the occasional hit on an egg, I have spun and then hatched four 10km eggs since they introduced the surprise box: dratini, larvitar, chinchou, dratini.
However, I barely care anymore, 10k eggs in the infinite incubator!
Lanturn Useful?
I noticed Chinchou got moved to the glorious 10k egg, so I decided to look at its evolution. And it seems Lanturn is surprisingly bulky in hp! If I invested in a Chinchou with decent iv and hoped it got cb/tb or cb/hp when it evolved would it be worth it? Or am I mistaken and Lanturn has no defensive usage?
Answers
In Singapore people fiercely defend gyms, because gyms never last long enough to get 50 coins, you have to take multiple gyms. In fact, gyms often don't stay long enough to even get 1 coin!
The #1 thing that determines how long a gym stays or goes down, is if there is a blissey in the gym.
Nothing else matters.
Lanturn with electric moves used to be a great (best?) prestiger against Gyarados. You could kill a Gyarados with 2x CP with only a bit of doging. It even could take a hydropump hit without suffering too much. But now that the CP of the attacker doesn't matter anymore, I barely use mine.
As a defender... maybe. The problem is that its electric moves are not a good shield, only SE against water and flying, so I think it would be an easy target for usual water counters, especially grass mons.
I don't think IV matters much anymore, so don't evolve a hatched chinchou, the CP will be too low, evolve a high level catch instead.