Why are White Dwarfs located in the lower-left area of the H-R diagram?

They have hot surfaces but are intrinsically very dim because of their tiny size

White Dwarfs occupy the lower-left region of the H-R diagram because their position reflects a combination of high temperature but low luminosity. They are the small, dense remnants left behind after low-to-medium mass stars, such as the Sun, have exhausted their core fuel and shed their outer envelopes. Because they are so small—often only Earth-sized—their total surface area is minimal. Even though the material remaining is extremely hot (placing them towards the left on the temperature axis), their small radius prevents them from emitting a large amount of total energy; consequently, they appear very dim when measured by intrinsic brightness (low on the vertical luminosity scale). This characteristic positioning clearly separates them from hot, luminous main sequence stars or giants.