Bitcoin Core disagrees with you:
This is experimental software
The warning not to put all your money into BTC is also still correct. Just like it applies to any other investment: diversification reduces the risk of huge losses.
Do not mind my little knowledge about this, but I think people can run full node even without Bitcoin Core? There are other full node wallets. Is that warning not pertaining to Bitcoin Core but to bitcoin generally? All other nodes still kind of depending on Bitcoin Core to run full node?
With how how see bitcoin today, it is been better than the software the banks are using in term of security of your coins. I think bitcoin developers just leave it for investment advise.