You grind out weapons so you can have them when they’re good and get use out of them before they are sunset or nerfed or whatever. Spare rations for example, I grinded for this gun more than anything else I have ever grinded for in destiny. For a few months the gun was completely dominant in crucible - the range of ace of spades but faster firing, legendary, and offering more perks like rapid hit and kill clip. It was unbeatable, the strongest primary the game has ever seen for crucible. It’s still top tier now although not quite as good since the range nerf, but no matter what it is getting sunset in the fall. Do I regret spending 30+ hours grinding for it just for it to be sunset? No not at all. Because thanks to me putting the time in, I got to use it in its prime. If I had known it was getting sunset I’d still have grinded for it just to have for the few months of it being so good. Destiny has a trend of making things easier to get over time and rewarding those who wait. For example seasonal exotics ending up obtainable from the exotic cipher, seasonal legendaries ending up very easy to grind from umbral engrams, dire promise going from costing people thousands of shards to being in the world pool. But the thing is if you wait for the stuff you want to be easy to get you wont get as much time out of it. You grind so that you can have the good stuff when it is good. Imagine if you had known a year ago that sunsetting was happening so you opted out from grinding out mountaintop so that you didn’t waste your time. So you get to save your time, but you are willingly handicapping yourself by choosing not to get the best special weapon in the game for PvE. If you just put in the few hours to grind out the quest you’d have a year with a phenomenal weapon, even if it’s “just a year”.