The stated point is to prevent central banks from printing currency / inflation. The claim is that crypto today worth 1% of the world's BTC will be worth just under 1% of the world's BTC in 2300, at least barring e.g. progress in quantum cryptography, a sunspot taking out digital infrastructure, or similar.
That's probably socially harmful, but it is the claim.
Inflation is increasing prices, which has causes other than central banks putting more money into circulation. When Bitcoin’s value drops, prices in Bitcoin increase so it experiences inflation regularly.
The former is inflation of the money supply, which causes price inflation when it exceeds economic growth.
The latter is volatility.
Apples and oranges.