What does the "convert to sRGB" do in the batch settings?

What does the "convert to sRGB" do in the batch settings?
If the original TIFF images are already in sRGB color profile, will having the "convert to sRGB" option enabled cause an extra process, or will it skip?
Is it better, or faster if I turn this off?
If the original TIFF images are already in sRGB color profile, will having the "convert to sRGB" option enabled cause an extra process, or will it skip?
Is it better, or faster if I turn this off?