In my work, I use Gurobi and other proprietary/free solvers to optimize some objectives big banks care about. It's not uncommon to use solvers in finance to optimize some metrics of a portfolio. A lot of people I have met in conferences optimize their supply chains (think things like: find the best pattern to draw the various pieces of my table in these planks of wood such that it minimizes wastes, find the best route to deliver my 100 packages...)