Not saying it is a bad ability
But it’s undeniable that there are many fruits that are much more powerful and would be better suited for teach’s right hand.
invisibility offers no offensive abilities and gets countered by CoO.
Compare that to the mera mera no mi or Marco’s fruit.
For Shiryu to pick this random ass paramecia from a pre skip villain Sanji fodderized, there just has to be more to this fruit than meets the eye.