The content you create for YouTube must be unique in order to be monetized with YT Adsense. My niche wasn’t unique enough so it would not be approved for YouTube Adsense. Example: curated content. If you put together a compilation of unboxings, for example, adding nothing else to it, then it probably wouldn’t be unique enough according to YT. You’d have a better chance if you did that same compilation but with your commentary or voice over added. Hope that makes sense.