I dont see why you’d want to use landscape at all when you know meshes work better and you don’t even have procedural grass or anytning special that wpuld work “easier” with landscape.
A mesh with vertex paint will work eons better all around.
And,
They either cut the size of the landscape squares perfectly, or - somewhat more likely - they used decals and tiling images to achieve clear transitions in ortogonal zones. Afterall, it looks blocky.