There are a number of mechanics designed with the classic overworld tile system in mind. For anyone who hasn't played any of the newer Pokémon core series games starting with Sun & Moon, or has never played any of the games that came before Sun & Moon, one of the several changes brought about for the franchise in 2016 was the implementation of what one of my friends recently called a "free movement" system. Every game prior to this could be interpreted as playing on a sort of grid, or rather a collection of grids separated by loading zones, where any directional input assuming you weren't walking into a wall or other impassible obstacle would set the player character on a different coordinate tile in the game's overworld. Most of these grid-like overworld tiles were empty so the player character is able to move around, but a lot of these would also contain elements you could interact with, most notably different kinds of terrain that has a change of activating an encounter with a wild Pokémon when you step onto or into them.
With the shift to a free movement system that preceeded the non-linear development emphasis of modern core series Pokémon games on the Nintendo Switch, several under-the-radar mechanics have since been lost to time. Up until... I believe it was Diamond & Pearl were the first games to remove this? you used to be able to use the move Cut in the overworld to temporarily remove interactable tall grass tiles, turning them into functionally empty tiles until the tall grass grew back. Speaking of Diamond & Pearl, the Sinnoh games as well as the Kalos games had a postgame exclusive Key Item called the Poké Radar which had notable use for finding Shiny Pokémon in the wild. I bet there are at least some people out there who didn't even know the Poké Radar made a return in Pokémon X & Y. In the Hoenn region games of Pokémon Ruby, Sapphire, and Emerald, the player was effectively required to have knowledge of the overworld tile mechanics in order to find the new Pokémon Feebas, incomprehensibly good luck not withstanding, but the extreme effort required to find and raise this Pokémon not only rewarded players for knowing more about the game's mechanics, but their efforts would ultimately culminate with being able to obtain one of the new region's most recognizable Pokémon.
Those are just some of the examples I can think of that newer regions from Alola onwards distinctly lack. The shift from the classic overworld tile system to free movement and non-linear emphasis has many positives in my opinion, but this comes at the cost of some of the extra worldbuilding emphasis that gave classic core series Pokémon games a lot of their nostalgic charm for millions of fans around the world.