This is trivially true (all civilizations end, the sun burns out, nothing is permanent) but the relevant timeframe is usually one's lifetime, and the stability of the currency over that timeframe is more important.
>> you're paying compound annual interest to the central bank in exchange for nothing
You're paying that "interest" in exchange for a more stable currency, a supply of liquidity that allows for progress/growth . If the central bank is doing its job reasonably well, that is. You may also be paying for the "feature" of money that allows you to transfer value to your future self with relatively little risk.