Hoarding is simply the same as saving. Savings are what makes capitalism a viable economic model. Inflation is a stealth tax from those who have last use of new money (the poor, middle class) to the pockets of those who have first use of new money (the banks, wealthy, government).
It is not quite so simple. Standard economists worry that if inflation becomes too low (or if there is deflation), incentive to hoard increases and incentive to invest drops, which could lead to negative growth, the bête noire of capitalism.
There is merit to the argument that inflation should match real GDP, rather than remain near zero, with deflationary effects. Even gold "inflates" as the stockpile grows from mining. Bitcoin will inflate at a greater rate than the world real GDP growth rate for some years yet. And if Bitcoin deflationary effects ever proved a constraint on GDP in a Bitcoin economy, then there is always Litecoin etc to take up the slack.
Also, those standard economists may well be in "academic capture" and parrot the view that serves their employers (central banks, government) best.
http://www.washingtonpost.com/news/volokh-conspiracy/wp/2014/05/18/regulatory-and-academic-capture/