Ah, if I get 100$ today, what is the decline in one week?
If you had $100 last week you could have bought .3 bitcoins.
Now you can only buy .25 bitcoins.
Your money is losing value.
this could be used against who say that the quote "you don't lose unless you sell" is bullshit lol
but with fiats, you lose even if you don't sell - because their inflation goes one way. your dollar will never be able to buy more than today.
If you know where to look, you can find cheaper prices, so that dollar can stretch further. The same can't be said for BTC at this point, as we're still limited where we can spend it, and we have to pay premiums to acquire it.