Eugene Gendlin found that people having certain skills manage to get better in therapy while people who don't have the skills don't get better in therapy. One of those is the ability to connect to what he calls the felt sense. Locating the emotion in the body and feeling it physically does create that connection.

Focusing itself is based on a lot of scientific research and the Focusing book is worth reading if you want details.

The Lefkoe method would be another method that uses what I describe here as step 2. The same goes for Silvia Mind.

Based on my experience with different change work techniques and the scientific studies on which Focusing is based, I think that the step of feeling into the emotion is very useful for helping the body to process the emotion.