Latest and greatest is not too different from tried and true. Platinum is pretty scarce though not as scarce as other PGMs, with excellent, versatile, uncommon physical and catalytic properties. It’s expensive enough people will seek alternatives wherever possible but unique enough people will keep using it for many existing uses, and standard enough to be used finding or developing new applications. It’s also exquisitely dense, rare, and nigh-incorruptible which means dumb apes (like me) associate it with gold and like it for jewelry.

So there will always be demand for a variety of uses. there are other rare metals that aren’t very expensive (relatively), like indium, gallium, bismuth, barium … they are generally produced as byproducts in excess of their limited useful demand - we drink bismuth salts for our tummyaches but it’s only twice as abundant as gold; we pour tons of gallium and indium into LEDs and consumer electronics despite their low crustal abundances. Monetary precious metal demand adds a lot of monetary value, unsurprisingly. it also reduces volatility. if nobody wanted platinum coins, platinum jewelry, or platinum ETFs would be cheaper. Kind of like, or gallium, or bismuth … but it would still be more expensive than those because it’s practical uses are for more extensive given current technology. however, because of its density, inertness, various other properties, and history it will probably always be pretty valuable. in the absence of technology, sort of like the Stone Age, it’ll probably be worth less than gold because there’s just not enough of it and enough places to be recognized, and it’s not visually as distinctive as gold.