The point of kintsugi is to emphasise rather than hide damage in an aesthetically pleasing way.
The Japanese word Kintsugi translates more or less as ‘joining with gold’, and
The story of Kintsugi is said to have begun in the 15th century when Japanese military commander Ashikaga Yoshimasa broke one of his beloved Chinese tea bowls and, disappointed with the shoddy repair job it was treated to, urged Japanese craftsmen to come up with a more pleasing method of repair. (Source)
If you wish to remain true to the tradition, precious metal (powdered gold, silver or platinum) is mixed with clear resin or lacquer. This enables you to see the gold or silver colour from the metal clearly.
There would be no reason why you cannot mix the metal powder into ceramic paste, but you would not necessarily see the metal in the join as clearly.
I have seen some people fix the pottery with ceramic paste then paint the crack with gold ceramic paint to emphasise. Painting the joins, or using pigment powders as you suggest, is not a true traditional Kintsugi piece as no precious metals are being used. But, it still plays on the tradition of wabi-sabi (an eastern philosophy of living that finds beauty in the damaged or imperfect).
For more on this, see https://www.bbc.co.uk/programmes/articles/326qTYw26156P9k92v8zr3C/broken-a-pot-copy-the-japanese-and-fix-it-with-gold