This feature allowed you to find stronger Pokémon in routes and sometimes initiate a Double Battle. There was also a rumor that Shiny Pokémon were easier to find in this grass which I am led to believe is true because my very first Shiny was a Cottonee, and guess where I found it? Yep, dark grass. In Black 2 and White 2, I think this was even more useful. The amount of Pokémon in that game was already pretty high and the dark grass made it even more useful to find them. WHO WOULDN'T WANT TO ENCOUNTER A METAGROSS IN THE WILD? But let's be honest here... we all used it to kill Audinos for their lovely experience. How did you use this feature?
Personally, I avoided dark grass patches, I would often get the worst of luck and end in a black-out. I can say in all the games, I never walk in the dark grass unless I have to for the game. Not for Pokémon, not for XP, there was no way I was getting in the dark grass
I used the dark grass to grind between gyms. The higher leveled Pokémon made it a prime spot to grind two or so levels before moving on. Eventually, mindlessly killing Pokémon was not the best idea, seeing as I got Lulu, my shiny Camerupt, from one of these patches.
