Thermal Equilibrium is a very useful concept in physics: almost everything we teach our students, from undergrad thermodynamics to graduate level statistical mechanics, is equilibrium statistical mechanics. Unfortunately, many systems of interest - from life to lasers - are far from equilibrium. We are interested in such systems.
Cynics would say that we are interested in all systems except for those in thermal equilibrium. They are, of course, wrong: we are often interested in equilibrium systems as well!
Here is my Google Scholar page.