The right image is an example of how turning chains affects your design. The 3-turning chain stitches joined looks obvious and disturbing while the non turning stitches look even and neat. The picture of on the lower left shows the first row of a plain granny square. The 3-dc group where the stitches joined looks thinner compare to the rest of the groups whereas the right picture shows the stitches are more even and balance.
This technique is particularly useful when you are making dc in round such as bags and tube shape items as it helps close the gap created by the 3ch.