This will allow your game to have a limitless amount of freeplay maps and people will go crazy making them. It is a win-win option, if you have the ability to do so.

Ive wondered this also, SDK for modding... & Mods most defo increase the life span, Theres games out there in the top 20 purely because of the modding community....I checked with Unreal & couldnt do much without the proper files...