I have used prime tabs in bottles before and many of use use Domino dots. Both simply adding sugar to each bottle. So why do I still mix priming sugar with water and heat until dissolved before pouring into the keg rather than just fill the keg and dump in the measure amount of sugar? I get dissolving it in a bottling bucket to make sure it is mixed in well for priming bottles instead of trying to measure out tiny amounts for each bottle.
I use table sugar and weigh out the amount using NBs handy priming sugar calculator.