The catch is, there's a 1 in 25 chance that when you come out the other end, you'll be invisible. Irreversibly.
Would you still use it? How many times would you risk using it? Who would you visit?
If 1 in 25 is too much of a risk, what chance would be acceptible? 1 in 100? 1 in 2000?
If you became irreversibly invisible, what would you do?