The Drago Plateau is home to a species known as the Drago, which is a type of creature that looks a lot like the T-Rex. It is located on the mountain that Alec lives on. Flint and Alec are the only ones who ever go up here while controlled, and Claus goes up here to get revenge against Hinawa. It also holds many other creatures, such as crows and trees. It's an easy place to gain items though, so this place does have a good purpose. It is at the very top of the mountain, a little ways from Ionia's house.
At the top, you'll find the guardian of the Plateau, the Mecha Drago. The Pigmasks created this beast to "make them cooler" as quoted from the journal you find earlier in the game. He is very strong, and can only be hurt after you stab the Drago Fang into his skin. Afterwards, the Baby Drago comes up and starts hanging all over his parent, and Flint wants to kill him. Alec holds Flint back, and that spot is never mentioned in the game again. You can always visit if you are in Tazmily Village though.
This is a good place to get things like Nut Bread and Beef Jerky. They have things like Running and Sprinting Bombs as well, but those are in presents, so it is impossible to come back and get them a second time. The other items are obtained by beating enemies like the vultures and trees. It's very easy to gain items as well when you are in the higher levels, such as over 20. Then just go back there and fight them to gain any amount of items. This is most recommended when you have 4 People in your party, so that you can carry quite a bit of items around. This is usually where Boney comes in handy, due to him being able to use items without actually being needed in the game. He isn't very helpful, but when it comes to Speed and Items, it will help you a lot.