Only people with the Byakugan can use Gentle Fist
I didn't think this needed to be said but apparently people forgot this here. I feel weird even labeling it a discussion because there isn't one.
Chapter 79.
You need to see the "inner coil system"/chakra network to use Jyuken. You cannot see the chakra network normally. It is the byakugan that allows you to see the chakra system. It is explicitly called out as the thing allowing them to attack the chakra network.
This is not referring to the tenketsu/64 palms. That will be revealed later and after this.
You can't just push chakra into someone's body and use jyuken with it; that's why the Hyuuga are terrifying.