According to SWGoH.wiki,
Datacrons are a resource in the game that allows players to give temporary ability and stat boosts to characters in various game modes. Datacrons can be obtained from Conquest, Territory War, and the Datacrons Store. Datacrons come in specific sets with each set offering unique bonuses for different factions and units. Datacron sets are only active for three months and then they are phased out for a different set. These new sets are activated each month when the old set is phased out. Datacrons require specific materials for leveling them up and rerolling bonuses on them.
What this means to the general public playing Star Wars Galaxy of Heroes is this – Datacrons are a necessary evil in SWGoH that you cannot avoid if you want to be highly competitive.
The toughest part about dealing with Datacrons is to find the best datacrons. Each set has their own stats that are enhanced along with factions and specific characters who are impacted the most, but not all datacrons are created equally. Finding the best datacrons can come down to an individual’s character roster, specific timing in where the game is trending and how the characters and teams are used.