Triangles, aka Tris, is the very foundation by which all objects are created as a drawn surface or filled surface defined by 3 vertices with in 3 dimensional space. A Quad or Polygon is an invention where two triangles are used and the dividing edge is hidden and it’s fill area is defined by 4 vertices but allows for better tool usage but at it’s core be it tris or quads triangles are still used.
In most game engines the hidden edges are exposed as in most cases the target application can not support the properties that defines what is a polygon or a triangle as a feature that is unique to a given 3d application be it 3ds Max, Maya or even Blender.
Overall it’s not so much as to which is better but rather what purpose needs to be served as a “choice” as to artistic prerogative of design. In 3ds Max, which is what I use, quads offer better editable as well as better smoothing group control where tris offers the option of lower surface and vertex counts for LOD or low poly requirements.
In the end though it really does not matter as long as the result is a pleasant rendering and the surface supports the applied material. .