Sun-synchronous orbits pass over the same spots on the ground at the same solar time of day (not necessarily _every_ day). The orbits are designed this way on purpose: it is very useful in remote sensing to have the same lighting conditions for repeated scenes, in order to detect changes in vegetation, topography, or human activity.

The orbit is fixed with respect to the Sun, so the times in and out of the Earth’s shadow are always the same. This can be very useful for certain studies: limb observations at sunset/sunrise for deriving concentration vs altitude of chemicals, or for always having light on solar panels or shadow on light/temperature sensitive instruments.

The orbit is achieved by a particular combination of height and inclination (tilt), so that the orbit precesses at the same rate as the Earth moves around the Sun (i.e. about a degree each day). Because these orbital parameters are fixed, everything else onboard has to be designed around them, like aperture/resolution trade offs, scan patterns, etc.