The reason this matters is for determining another question: Can a creature under the effect of the True Seeing spell see a creature under the effect of Nondetection inside the area of a Darkness spell?
The true seeing spell description reads:
This spell gives the willing creature you touch the ability to see things as they actually are. For the duration, the creature has truesight, notices secret doors hidden by magic, and can see into the Ethereal Plane, all out to a range of 120 feet.
As such it apparently gives the creature truesight (by means of divination magic). So the creature is granted a new sense, but is the use of that sense mutually exclusive to the use of their normal sight?