If you have both versions of a game, which one is your "main" and which one is used for several playthroughs?

For me it is still a bit on the fence.

On the one hand I want to play my favorite version of a generation over and over.

On the other hand its nice to have my favorite version as my "main" version, where I got all the Pokémon available and beat it with my favourite Pokémon of said version, be able to catch anything since ive completed the story and got the nation dex and so on.

So what about you? Do you like to have your main version save and sound or do you want to experience your main version over and over.

To be fair, usually there arent much differences in gameplay from each version. I could argue with the story or something but its Pokémon we are talking about. But I dunno it somehow feels better to play the favourite version over and over again with cool challenges or something like that.