is it intentional that one arrangement of the letters is correct when another, equally correct, arrangement is wrong? eg 'L L I P S' can be 'SPILL' or PILLS, bu

is it intentional that one arrangement of the letters is correct when another, equally correct, arrangement is wrong? eg 'L L I P S' can be 'SPILL' or PILLS, but only PILLS is accepted. Similarly for NOTES being 'correct' but STONE being wrong.