Particularly, so long as it is preceived to be likely to increase rapidly in value, it encourages them to use bitcoin as an investment vehicle rather than investing bitcoins in other things.
Obviously, if you want to consume things, you need to liquidate some assets to consume them, and if you've tied up your assets in bitcoin, you'll spend them for consumption.
There's not that much friction to exchange it for currencies. I just transferred a five-figure USD amount to an exchange, sold it for BTC, sent them to another exchanged, sold BTC for Euro, withdrew it on the other side of the world. All of that through two exchanges based in countries I've never visited. I saved enormous amount of money compared to just wiring USD -> Euro through my bank.
For every bad story your read online there are hundreds of transactions that went perfectly fine, but people rarely bother to write about their positive experiences.
Bitcoin encourages people to KEEP their bitcoins. Why use them to buy something when next month they're going to increase in value.