You're right, bitcoin's deflationary nature means that present spending is more expensive than future spending.
I'm no economist, but I don't believe that statement is true. Yes, bitcoin is limited in number, but that's no guarantee whatsoever that it's going to keep increasing in price. Hell, the purchasing power of the bitcoin I own has decreased by about 10% since last week, and I think altcoins have suffered even more.
It's deflationary by nature, in that if the demand keeps increasing the value of it will continue to increase due to the limited supply. Most other currencies have a ever increasing supply so the value keeps to decrease. I was not stating that the value will increase indefinitely, because it's conditional on the demand.