Also, if you are going to make the Interim Belt a silver, then why even have it at all. Just go full no mercy and strip every champion who is not able to make it to the Octagon for a fight that has already been scheduled.
For example, Robert Whitaker should have been stripped and demoted to number 1 contender for failing to make the Kelvin Gastelum fight. So, Israel Adesanya and Kelvin Gastelum would have fought for the championship belt. And if he ever got healthy within 12 months, then Robert Whitaker could have fought for the undisputed title versus Israel Adesanya.
This way, you don't have interim belts. You have stripped champion and a disputed champion, and they can settle score for the undisputed title.
This is better than making a silver belt, because you are essentially saying that if a champion gets legitimately injured like Robert Whitaker was, then the next guys up are not good enough, which is BS. On any given title fight, any fighter can become champion. Just ask Michael Bisping and Matt Serra and Conor McGregor.