As you might know, there are three current types of tool boxes, health, attack and energy. They may seem okay right now, and the health and attack are fine, but energy tool boxes behave a bit different.
Health and attack both give more health and attack as they grow in stars, but energy, they stay the same. The higher the star, the... same the energy? But there is, even more, incentive to use lower star energy toolboxes.
They cost less. I tested out a 5-star wood energy and a 5-star metal energy, and they both gave one energy, but the wood tool boxes, cost less.
At first, I thought it didn't matter how I used my toolboxes because I'll always get better ones, but that is clearly not the case with energy toolboxes.