It works in this particular case because anything outside the 0,0 to 1,1 coordinates are mirrored or tiled. Since your pattern is designed for infinite tiling, than there are no appearent problems. However if you had a texture that wasn't designed to tile it wouldn't work well.

Also, rather that moving the UVs out, you can use the texture's placement node attribute to define how many time you want the pattern repeatead across a surface.