It should be easier: I used iMazing for this. And the Video Camera app: https://itunes.apple.com/us/app/video-camera+/id441433868?mt=8
has the ability to Copy to Camara Roll. It's a dollar.
Open iMazing http://imazing.com/download (don't buy the game) and I go to the the Video Camera icon the left-hand menu. A huge window is on the right side and you can drop & drag your movie into the window and it'll be in the Video Camera app on your iPhone.
Open the movie and in the Video Camera app and in the bottom right is an icon to share. Copy to Camera Roll.
It's a workaround, and hopefully will work a year from now
has the ability to Copy to Camara Roll. It's a dollar.
Open iMazing http://imazing.com/download (don't buy the game) and I go to the the Video Camera icon the left-hand menu. A huge window is on the right side and you can drop & drag your movie into the window and it'll be in the Video Camera app on your iPhone.
Open the movie and in the Video Camera app and in the bottom right is an icon to share. Copy to Camera Roll.
It's a workaround, and hopefully will work a year from now