We all live with the knowledge of impending death every day, it's something we all have in common that will come for all of us at some point.
For a lot of us, the hard thing to deal with is the uncertainty about when. We might keel over tomorrow, or even later today, but if we live our lives like that's the case, we might screw ourselves over if we manage to live for another 70 years. We might fuck up our health, leave ourselves poor, homeless, ruin our reputations, etc.
It's a balancing act to squeeze in as many good times while we can, while setting ourselves up to have many more good times in the future and for others to continue having good times after we're gone. Plan too conservatively and you miss out on a lot of stuff now, but if you go completely balls to the wall now you leave yourself nothing to work with later.
Put a hard limit on things with the world ending though, and you remove a whole lot of uncertainty from the equation. You don't have to worry about making things last, or the long-term consequences, you get to live entirely in the now, because there is no (or very little) later.
I'd rather have another 50+ years of normal good times and people to continue having that opportunity long after I'm gone, even if it means going to work, than a scant few days or hours (or whatever scenario we're imagining in this case) of raucous debauchery, but if that's the cards I get dealt and theres no way of changing that outcome, I can either mope about it and waste the little time I have left, or I can lean into it and make the most out of it.
From where I'm standing, anyone who'd rather mope is the one with real issues.