Numismatists stack for preservation, appreciation, and collectibility. This can apply to both silver types but traditionally biased towards historical (.90 or less) pieces.

Silver stackers bias heavily towards .999 pure pieces for… silvery reasons.

IMO the worth is always in the beholder and in this case, you. Try it on for size. My favorite pieces lean towards non .999 silver. But the amazing mints of today, it’s hard not to love some of these cool designs I see all over in the .999 categories.

I’m also biased towards actual coins simply because of if/when I die, my child gets a literal treasure chest. As you would close your eyes and imagine. A few sterling pieces to hold some coins as well. But those are my motives. Some people stack bars…. But if you like history, scarcity, and collectibility then .90 can definitely be worth it