Electrical conductivity spans an incredibly large order of magnitudes (30!) from insulators to metals, and can even be infinite in superconductors. Knowledge of how to control it has allowed for the computer revolution, and ever increasing miniaturisation
Thermal conductivity, while only spanning arround 10 orders of magnitude for known materials, is still crucial for many important technological advancements, from jet turbines and space travel to USB drinks coolers.
To truly appreciate these achievements, it is vital to have an understanding of how conductivity arises in materials. There are simple models that can be used to predict the behaviour of many materials; close parallels exist between thermal and electrical conduction in metals, whereas the conduction mechanisms in non-metals are quite different.