Not defending BitCoin (I won't be buying any soon), but I think the author doesn't realized that BitCoins are divisible down to eight decimal places. It's difficult for me to imagine a currency which is so divisible being "hoarded to death".
The divisibility has no bearing on the hoarding. The hoarding comes from the expectation of increased value over time, not the number of decimal places. If you have something that you think is going to steadily appreciate in value over time, why sell it now?
* When you're dead all your savings are worthless (to you), so your likely to spend most of them before then.
* Some consumption cannot be postponed: you need food, a roof over your head, transportation, etc.
* Time has value. For example, if you wait another 6 months the same amount of money (bitcoin or not) will buy you a better computer. This is likely to hold true in the foreseeable future. Still people do but computers (and phones, etc).
* There's opportunity cost: even if your savings increase in value over time, investing them in something could increase them even more.