I think we all collect for enjoyment of the hobby. For me, it's not PM coins over base metal coins per se, it's more a case of coins that were real money versus coins that are fiat money, such as modern US clads. It's just that, coincidentally, most of those coins I consider real money happen to be silver and gold. But not all of them — older large coppers had real, intrinsic value, and consequently I find those appealing as well. But there really is no wrong point of view on this issue. "Collect what you like" is and always should be our mantra.
A word or two about precious metals in coins vs common metals. 1. Silver and Gold are much more malleable than a Copper-Nickel Alloy. As such, the designs can have much higher reliefs and much more POP! 2. Quantity over Quality has been the US Mint and the Mints of the World mantra since the early 70's in that, given population increases, the demands for fiat money has increased a hundred fold if not more. This increase required if not DEMANDED lower profile coinage on higher speed presses which basically equates into designs that simply have no POP. Even the "Collector Issue Coins" produced in Silver and Gold have no POP because the designs are of such low relief. Comparing the POP of the CnClad 50th Anniversary Kennedy with the Low Relief version of the coin of the same year merely highlights what I am saying as one has POP while the other has nothing other than an extra consonant which makes it POOP. As such, many collectors prefer coins minted in precious metals and all prior to 1965. I believe that its design related and first impressions with the overall quality of the designs.
No, in fact I collect almost exclusively base metal coinage. I have little interest in silver and absolutely none in gold.