Whether you should or shouldn’t wear liner gloves is largely a matter of preference. However, Here are two reasons you should wear them.
Firstly they will increase the warmth of your hands by introducing an extra layer underneath your gloves. This is especially useful if you suffer from poor circulation. Secondly, If the inside of your glove gets damp from perspiration, or just gets a bit smelly, you can simply swap out the liner, and you effectively have a new pair of gloves!