If someone only wants to buy, say, $100 worth of bitcoin just to get their foot in the door and they don't put in the time to research how to keep their local wallet secure and make sure their computer/phone has not been hacked, they're very likely better off keeping that small amount of bitcoin with a service like Coinbase (and set up 2fa!)
Of course if you play with bigger amounts, and you take the time to educate yourself further about taking custody of your own funds, then I completely agree with what you've said.
If someone only wants to buy, say, $100 worth of bitcoin just to get their foot in the door and they don't put in the time to research how to keep their local wallet secure and make sure their computer/phone has not been hacked, they're very likely better off keeping that small amount of bitcoin with a service like Coinbase (and set up 2fa!)
Of course if you play with bigger amounts, and you take the time to educate yourself further about taking custody of your own funds, then I completely agree with what you've said.