In my opinion it is my man. The idea for rotating pokemon is that in certain battles the 6 pokemon you usually use are not always good in every scenario. For example, say that you're usual 6 pokemon is great at countering Titaina's team but, those same members will get easily counter by Amaria's team. You see what I mean? Pokemon rotations make sure you have backup/certains they will keep ready for any battle that any of your usual 6 pokemon won't be effective in. Plus, helps you strageize more easily and help overcome incrediliy diffcult battles espcially for a diffcult game Reborn.