the easiest way to remember this is to think about how your legs work on a multi-geared bike. In any gear, the muscles are the same strength. Yet, you can vary the gear ratios so your are more optimized for hills or flat ground.

Often, we don't realize that a dc motor is faced with the same physics, because an electric motor torques very well at low speeds.

However, a steep enough hill will exceed the torque capabilities of a motor, and if you have the ability to gear down, you would benefit much like you benefit from your granny gear.