While playing, my puppy likes to try and bite me occasionally. If she succeeds, it's not a full on bite, nor is it aggressive. But should I discourage this behavior? If I proceed to allow her to play bite, what could I expect when she's older?
Consider how others will react. You know the dog is just grabbing, gently -- but if she does this to someone else, they may panic.
If you do permit this, you should clearly train her to distinguish when and where it is appropriate. That's going to take more dedicated effort than simply training not to do this to people.