There can be a way out there to translate from USD to Bitcoin. That would not be such a problem. As for the unstable aspect... I don't see the USD keeping its value. Actually is bound to crash. Up until now, it was a good reason to have it, since it was the reserve courenci of the entire world. This status will be lost. Is a matter of time until that happens. BRICKS nations already do economic agreements to move off dollar as a medium of exchange, and when they will take more concrete actions, USD will just crash.
With the Bitcoin, having it under public control and open source system, the complete crash of the system is just too hard to have. Most people involved in this process experts in their field and any flaw that may become apparent, can be fixed.
As for bitcoin mining bots in malaware... any currency has people trying to exploit it. That is not the problem of the bitcoin itself, since there are malawares that steal credit card info and no one has a problem with that. Most times they blame the user in those cases... why any other way now?