I wouldn't call that a bug as preserving value over time is a required feature of anything pretending to be used as money. without this feature, no one would be using it or abandon it quickly if it fails to offer this option. The history knows numerous examples when currencies stopped being money, then got abandoned and forgotten. On the flip side though, it attracts various parasites which hope to get something out of nothing for just holding a few currency tokens (not necessarily bitcoin), expecting that their value will rise in due course, and thus the holders will be able to buy more with less. Obviously, someone has to pay for this seemingly "free" lunch, and these are the people who make it possible but definitely not the holders themselves. That's basically why they are parasites sitting at the top of the food chain.