Invision and similar apps like it, technically, do everything Red Pen does. But in doing everything, they become overwhelming to use. The clients I worked with on freelance struggled to understand Invision: the signup was lengthy and distracting, the mode switching confused them, they lost their place in the hierarchy— it required me to prod them to use it, and it produced shallow feedback. Conversely, I have a folder of Red Pen customer emails who report their clients produce significantly greater feedback.
This word's meaning has been hugely diluted but "experience" matters. If you're trying to communicate something, you want your message to come across as you intend. If you want someone to be honest with you, you want them to feel at ease. That's the difference. It's easy to give feedback on Red Pen.
