You're not thinking this through.Don't be a jackass and throw personal insults at people who disagree with you.
I didn't dismiss your idea as ridiculous because it is new. I dismissed it as ridiculous because it is ridiculous.
If he is good enough to play as a WR, then give him a roster spot straight up. This could happen.
If he is good enough to contribute when the QB1 is healthy, then give him a roster spot straight up. This could happen.
If he is better than Zappe, then give him a roster spot and make Zappe the emergency QB. This could happen.
But it is ridiculous to make the 2nd best QB on your team the emergency QB and hope nothing happens to the starter.
Let me make it simpler for you.
Let's say Zappe is a little better than Malik, even accounting for Malik's unique dual threat skills. So with Mac out of the picture, Zappe should be your starter.
But in a game scenario, Mac + Malik >> Mac + Zappe because Zappe only helps if Mac is injured, while Malik dressed as QB2 with his unique dual-threat skills (let alone WR etc) adds value to all the games where Mac is healthy. Zappe can only add his small incremental value over Malik in the one game Mac is hurt in.
In that scenario, you get much more value dressing Malik than Zappe.
It may turn out that Malik's value add to Mac is too small to justify sitting Zappe, but it's hardly ridiculous to contemplate.