Found this bug while recording for YouTube, while I am not sure if this is intentional, it works in both Survival and Creative, and it only takes 10 punches to kill a mob. 11 for zombies, of course 😛...the particles are not crit hit particles, they are the enchant particles that indicate extra damage.
I was about to say something before I found this, I was looking at it, and saw that it doesn't do extra damage (At least that's what I found), but instead it just activates the sharpness particles no matter what enchantments (if any). This is quite strange to me.