1. Storage
2. Payment rail
If your storage is solid (e.g. keys in brain wallet, account in crooked bank, money in shoebox) and the payment rail is solid (e.g. gold, cryptocurrency, cash), you're good. (To clarify, "solid" here means "beyond the legal-regulatory system", which means the rules aren't trumped.) Otherwise, you aren't.
I say that Bitcoin has "finality," because it does the job of payment rail with 100% irreversibility.
Grant that Bitcoin is a mediocre storage (1). But the payment rail (2) truly is irreversible. The combined system of two disjoint parts, built out of bitcoin-as-storage and bitcoin-as-payment-rail, is not.