They can build the parts of the chest that are usually weak in many guys, but you have to use some weight and do slow/slower controlled reps.
Seems like the close grip would just put more workload on your triceps.....
I do them during my tricep workout.
But you feel them in your inner upper chest area as well?
Yep, like you feel anterior delts during bench press because it's a synergist muscle. I guess the closeness of the grip activates the inner chest fibers.