On top of that the fact that you'll get RS gold more rewards for opening Medium Casket than you would for an Easy one (so you could expect items like shield h3, shield h2 or the helm the h3). Alongside being able to find Ranger Boots from a separate drop-list, you'll also get Spiked Manacles that cost over 1 million. Other benefits aren't nearly as valuable as the two items mentioned above.
Even though it's similar drop tables with regard to value Medium Casket and is a hard difficulty to easy, you also have the possibility of rolling from the hugely rare table. You can pick up a selection of very expensive items like 3rd Age Equipment and Gilded Parts that have a value of tens or even hundreds in millions (like 3rd Age Platebody). Additionally, items from the exclusive drop table are extremely valuable as there are four items which cost more than 1 million gold. Furthermore you will get more roll at rewards with a Clue than you do with a Medium One, so in general you should get better drops.
Just like with the previous casket, you'll get a possibility of winning unique and mega-rare items with values of tens of even hundreds of cheap OSRS gold millions. The difference between this casket and the previous one is that it has higher chances of receiving Gilded drops, as well as a bit smaller chance for Third Age items.