Hi Greg,
Lovingkindness practice is generally considered a samatha or concentration practice. It develops the ability to stabilize attention while also opening the heart, and breaking down the barriers between self and others.
If you maintain awareness, in Culadasa’s system of samatha-vipassanna, you will be developing insight while you are training your mind to stabilize attention.
For example, as you are developing the feelings of lovingkindness, you will notice other things in your awareness. It will be particularly helpful to be aware of any resistance that you might have towards the practice or generating loving feelings towards difficult people.
Developing equanimity and lovingkindness towards whatever you experience can definitely benefit your practice. For example, if you are frustrated by your progress in meditation you can learn to soften into that experience and accept where you are. Physical pain is also a good opportunity to practice lovingkindness towards your experience.
Hope this helps,
Blake – Dharma Treasure Teacher