“tris” is the word that mean triangle in mesh, mesh(geometry shape) is constructed from triangles.
also one “face”(quad) = 2 trangles.
normals refer to quads(face direction) [if i good remember not tris, but quads.]
Tris have position, correct, each verticle of tris have position, but please note UV is 2d coords, while verticle have 3d coords. its just about how you want map your model triangles to match 2d coords in UV.
what i said was that some “tris” what is almost not visible in viewport, while doing his projecting solution it would have “too small area in 2d UV coords”, for color it would be ok, but if you would want to perfectly texture model, then you need better UV than a projected one.