> fast
Not fast. Most cryptocurrencies have unbearably slow transaction or confirmation times. Maybe if you are buying a car, they will be confirmed by the time the paperwork is done. Even with initiatives like the lightning network, it's still slow. So much so that some of the major exchanges will tally your transactions off-chain, to be confirmed later.
> cheap
It really isn't. Be it gas fees or computational power
> secure
Eh, depends. Surely the transaction itself may be from the blockchain's viewpoint. But if your coins get stolen or your exchange gets hacked you really have no recourse. And that's just one issue. And before anyone says "hardware wallet", exploits have been found for those as well, assuming they were even secure to begin with.
> anonymized
They are not anonymous. With a few exceptions, all transactions are visible in the chain, forever. This works as long as you never need to convert to/from fiat. The moment you do, your identity is exposed - even retroactively. It's way worse than cash. Tumblers only help so much.