Is it really that hard to understand? I calculated the probability that the protection applied to the co-leader wouldn't be wasted, but would actually be useful. And it's extremely low.
And is it so important for you to use all the Night Actions? If it can harm, then you shouldn't use it.
In the core of your reasoning, it turns out that why should the Mafia kill at all? Evidence is revealed, especially with Hos, it's not that complicated and it's clearly visible.
This is a random factor; they may consider it, or they may not, and they may just silently execute. No sane Mafia will bet on it.

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!
