Why streak in an agar slant medium in a straight line rather than a back and forth wavy inoculation from side-to-side on the slant?

Streaking in a straight line on an agar slant helps to isolate individual colonies of bacteria as they grow. A back and forth wavy inoculation could result in overlapping colonies, making it difficult to observe and identify individual colonies. Streaking in a straight line also ensures a uniform distribution of bacteria across the medium.