You introduced the "central bank money/21 million coins" theme, not me, and I am not confused by the concepts.
I don't know what you're confusing, I only guessed. you're confusing _something_ because you're drawing the wrong conclusion.
Say you sign a contract with me today owing me 1000 Btc, and at the date of maturity, Btc have appreciated in value
value relative to what? to USD? to goods?
doesn't matter at all for banking.