Yeh, the linked information is kinda right ely.
They somewhat skimmed over several issues;
1) you can use a
shutter speed slower than the flash sync. speed to allow more ambient
light to record.
2) the actual sync. speed has more to do with how the
shutter curtains in the camera actually operate rather than any effect they have on controlling flash
exposure.
3) the use of a flash
meter is worthwhile especially when using film but also if the digital photographer is unsure of, or in-experienced in, evaluating
exposure and histograms.