That statements not a given. If it were so, people would not use credit cards.
In the scenario where you believe bitcoin will be worth $100,000 and you have $7,000 or 2BTC, you decide to buy a computer for $3,500. If the remainder of your value is in dollars, you will have $3,500 in value. If the remainder of your value is in bitcoin, you will have $100,000.
The depreciating asset you've invested in here is the macbook, not bitcoins.
I have a 1.4 bitcoin T-shirt. I don't regret it one bit.
Is that you?