Temperature has no purpose because Players can't manage it.
The heat mechanic should be turned upside down.
Heat should be based on partly external temperature and partially based on local heatsinks/heat sources like Ice voxels, shade, or tunneling underground. Pressurized environments natural and Artificial should lead to more heat retention. The color chosen for a suit or skin should absorb more heat Heat, the darker it is. from Machinery in an enclosed space (like a tunnel) should cause a cumulative heat build up to a point to actually raise the temperature in an area. For it to be manageable there should be a heat pump blocks to increase/decrease the heat level in a radius outside, or an entire grid, when inside. Heat, too much or too little, should just cause you to use O2 and energy faster and also add to the inaccuracy of rifle shots.