...So you're basically justifying it by saying that it's in other games, though such a thing is usually considered a flaw of such games?
Pointing out that it exists does not equate to justifying it.
But part of the game is exploration. And you often have to revisit areas anyway. In this sense, pretty much every game in the genre has a backtracking element
But I don't see how marking on the map the locations of the Treasure Pods you do find before you can open them is a negative toward the game?
It's less about being a negative impact, and more about
is it really needed?The game map is large enough that it can be memorised, along with locations of certain pods.
Why are we discouraged from exploring before the end-game?
You're not. When you find a Gordo, what's the first thing you want to do? Burst it. When you burst it, it drops a key. You find a Gate. You open it. You go in. You explore. Get new slimes and resources to use back home. You're encouraged to pop Gordos to progress further into the game; Quarry and the Blanket, then the Ruins, then the Glass Desert. And now Ogden's Retreat and Mochi's Manor.
When you purchase The Lab, it does state that only experienced ranchers should use it, and it costs a large amount of resources (and it doesn't state it, but also time). The idea behind it is progression. The Treasure Crackers are earned by building a large amount of gadgets, and the final tier is itself rather expensive. The idea is by the time you get the purple crackers, you've already progressed to the point where you've made significant headway into Slime Science. And by extension, gotten to the point where you can open every treasure pod on the map.
By the time you've built 100 gadgets - usually extractors which are made entirely with plorts - you should have gained enough resources to make the gadgets and decorations from treasure pod hunting after unlocking the MKIII.
You've got to remember that Treasure Pods are essentially Slime Rancher's equivalent of a late-game collectable item. For green and blue, maybe far earlier. But what some people do on games with collectables is wait until they've either beaten a game or gotten to the point where they have full access to the map, and get them all at once.