You all heard her when she asked Ellen to join her; if that's how she sounded just from saying a few words, WHY would you want to hear her sing it live? For the type of song it is, and the type of artist Jennifer is, I would much rather be entertained by the performance she gave then having her stand there to focus on vocals and perform some little routine where she throws an arm and leg out every 10 seconds.

HIHIHIHI
Even though Jennifer isn't the most musically competent - but then it's not like she acts like she is, by miming huge auto-tuned ballads - she actually does have a stronger voice than Rihanna. For starters, I have heard J.Lo sing in key.
Also please don't use God's name in vain; how can you imply that God's judging somebody, after you judge another human being?