Well, cryptos aren't really money so actually sending money via crypto requires transferring crypto from a bank to an exchange, making a purchase, withdrawing it to a destination wallet at an exchange, selling it, and transferring the proceeds to another account. That takes days, requires multiple transactions and costs boatloads of fees. By constraining it to transfer of an intermediate representation you're not making a good faith representation of the process.
Second, the only thing you can do better with crypto than a centralized exchange is crime, grift and regulatory arbitrage. What you're describing is the third. Sending money in any classic fintech system takes milliseconds. What takes longer sometimes is AML/KYC and security. Crypto pretends those don't exist. Like any other regulatory arbitrage you can certainly make things faster or cheaper, for instance by dumping chemical waste into lakes. Once again comparing a car to a little buggy with a 2-stroke engine and no catalytic converter on the basis of fuel efficiency is disingenuous too.
Anyways, sending "large amounts of money" isn't a problem most people have by definition. And if you actually do have large amounts of money, sending it around isn't an issue. I've had six-figure domestic wire transfers clear instantly with no questions asked from my brokerage account, free of charge, same day. The first time they called to check. I didn't mind.
Most of the world has free or nearly free instant transfers. Europe has SEPA, the UK has FPS, Canada has Interac e-transfers, Australia has NPP. The US is getting RTP and FedNow in 2023.
[edit] In fact, the cheapest way to move USDC from FTX to Coinbase is actually to request a free wire transfer from FTX to your bank account, and then either a free wire or ACH from your bank account to Coinbase. Saves $25.