It would be really helpful if I could go to the item page for Skull Coin, and see that I can get them from Mystical Chest 02 and Grab Bag 06. Similarly, if I go to the item details for Grab Bag 06, it would be helpful to see that I could get Orange Juice, Lemonade, Grape Juice, Wine, Ancient Coin, Steak, Fishing Net, or Skull Coin by opening it. The current item info pages for bags doesn't have any info about what they contain, other than text descriptions which are somewhat helpful ("Contains a random assortment of keys") or flat-out unhelpful ("Contains valuable items").
Currently you can see what chests contain, but this is one-sided. If I need Skull Coin for a quest, it makes more sense for me to look at Skull Coin's item info page as that already has info on where I can get it (Pets & Location). I usually don't think to go to the Locksmith and click each chest to see whether they contain it, or the library page to see if any bags have it.
