It's not "better". Pool store clerks are trained to think that powdered chlorine compounds are somehow, magically "better" than LC/Bleach.

However, unless your Calcium levels are high (over 400), you have nothing to worry about and it's perfectly OK to use it instead of LC/bleach. But watch your Calcium Hardness levels.

Despite that, unless you have low CYA or high pH, I would definitely say Cal-Hypo is better than Di-Chlor powder or Tri-Chlor tablets.