Store Bitcoin in Cold Wallets!
I think as cold wallets like Ledger (their newest wallet with iphone type UI launching in march) and Trezor become more usable the dominant model will become people holding all bitcoin in cold wallets. There are some distributed exchanges like uniswap but still hard to use. Until these get better centralized exchanges like Coinbase will still have a business providing an on-ramp (link checking account or card to exchange) for users buying crypto using USD or other fiat currency. They can still make decent spread and transaction fees but over the long term there is no question that the only way to hold crypto is in a cold wallet.
The best place to store crypto is in cold disconnected wallets, not invariably-hacked exchanges, which gives the whole Defi sector a bad name. Would any FT reader leave all their money in a Thomas Cook Travel Money exchange? After all, what is the purpose of an exchange?
Lastly, the only way to justify any crypto purchase is if you believe that it has a non-zero probability of becoming a viable asset class so perhaps worth the risk to have a very small (maybe a fraction of one percent to a few percent) allocation to crypto. Furthermore, I would only buy bitcoin or ether (useful on other block chains due to its better on chain programming ability). All other crypto are either lottery tickets or penny stocks in random companies or are like money market funds (stable coins) that are not clearly backed.