I disagree with the conclusion but the argument is well presented and I don't think unfair.
Bitcoin is indeed deflationary, but this does not hurt spending at all. Spending is determined by supply of goods and services produced. Deflation simply changes the value of the currency, thus reducing the nominal amount spent while keep real spending constant.
What deflation does hurt is lending, as the rate of return has to exceed the deflation rate to make financing through borrowing profitable.
There's no way around this as an un-backed non-fiat currency like Bitcoin has to be limited in supply to have any value at all. It's its scarcity that creates demand for it, and makes it useful as a store of value.
Ultimately, the permanent deflation of BTC makes it a currency that no one wants to spend (Gresham's Law and all...)
Gresham's Law only applies when two unequal currencies have to be accepted as equal in value by fiat. It doesn't apply in a free market.
Most of the new adoption currently is faith-based, but the deflationary trend of BTC will eventually drive the weak of faith out of the market and leave only those people who get real value from the cash-like (or gold coin-like) features of BTC transactions."
The number of people who could make use of a cash-like digital currency is significant.