Because they don't know. They have just imaged the mineral veins, not analyzed them.
Judging by appearances (always dangerous), they are likely to be some type of carbonate (like calcite) or evaporite (like salt).
Looks like mud cracks that one would find in a playa(shallow lake that floods and dries) that has dried out. Cracks could have been filled in with wind blown sediments, buried and then have mineral replacement. You can find the same thing here on earth
So they have absolutely no idea if it is worth much or anything and considering the cost to get there it is worth nothing.
“Jackpot” in what sense? Scientific discovery I can see but not really a jackpot... Significant scientific discovery, yes.
Misleading headline. I’m quibbling I know but I’m in a foul mood about being misled and deception and foolishness in general.