Suppose that I am now undergoing suffering S on account of a greater good G. If there was no way of gaining G or something comparable without S or something comparable, and if G obtains, then I would rationally say: "It was worth it."
Notice that for the "It was worth it" judgments, it does not matter whether G is past, present or future. All that matters is that G be actual. You may wonder briefly how one can undergo suffering on account of a greater good. Time travel is the exotic case—I can get a tetanus shot in order to avoid getting tetanus in the Cretaceous. But the humdrum case is where S is a cost of the good G: perhaps I worked really hard to gain G yesterday, and today I am suffering exhaustion.
Suppose, on the other hand, I now undergo suffering S in account of a greater good G that occurs in some other possible world. For instance, I endure penury because I have spent my money building a robot that digs in my backyard looking for diamonds. I fully know that there are no diamonds in Texas, but there is a possible, though I am quite sure non-actual, situation where tomorrow someone will bury a treasure trove of diamonds in my backyard. In that possible situation, I will get very rich. But it is silly to endure actual penury for the sake of merely possible riches.
So for a good G to make a sacrifice S worthwhile, it matters a great deal that the good occur in the actual world. But it does not matter whether G occurs in the past, present or future.
This is unsurprising to eternalists. But it should be puzzling to presentists and growing blockers who think that present goods really exist while future ones do not.