This is the place, where I must refute.
You are missing very important aspect of the economy of today. We are no longer in production-only era of economics.
The key are the services. People cant simply stop to spend, hoping for price bump. They have obligated themself to pay for various services, like electricity, water, heating, all kinds of e-media, in general stuff we have became addicted to.
Exchange of money for goods is no longer about physical goods alone, that's why your model is inadequate.

So, "Why Bitcoin is not that good as currency?" let me answer your question as simple as possible, it is only because transactions can not be reversed. That's it. No mystery because in this imperfect world, full of imperfect people, perfect financial system that disregards human errors, can't be viewed as consumer friendly. I have zero complains about irreversibility but imagine all those technological-illiterates...  not a chance.