I was and still am unsure of a deflationary economy, however, I read someone's point, that even in a deflationary economy, people will spend on things they need or want. They need food, shelter, clothes, etc... but there are perceived needs, like a car, nicer clothes and shoes, hair cuts, etc... that people don't want to live without. In the end, even so a currency might be deflationary, people will still purchase these things. We have simply been taught to throw away cash on junk, spend it until you only have debts. It will definitely be a completely different mind set to live in a deflationary economy, but it may also be a healthier one.
A currency can be deflationary and be used in parallel with other currencies that are inflationary. Just because one currency is -relatively- deflationary, doesn't mean that the economy goes to deflation.
The "bitcoin = deflationary = bad because deflationary economies don't work" argument is flawed because it is based on the assumption that national economies are based on bitcoin, when they aren't.
Even if bitcoin was the sole currency worldwide, the major problem would not be the currency, but the fiat debt scheme that needs to be "serviced" with interest - something that a finite money supply doesn't allow. The unserviceable levels of debt are a far bigger problem than the currency. Inflationary currencies just make debt more "viable" in order to perpetuate debt-slavery for nations and individuals. And this is not predicted to stop anytime soon.