For new crypto trading, the Broker page in the manual has always had 2 steps:

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    First, register with a bitcoin exchange service where you can buy or sell bitcoin for dollars or Euro; examples: Coinbase™ or Bity™. Register there, enter your credit card or bank account data, and buy bitcoin. Credit card transfers are usually more or less instant, bank transfers can take some days.
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    Finally, register with a crypto exchange; examples: Bittrex™ or Binance™. For depositing bitcoin, the crypto exchange shows you a receiver address to which you send coin from your wallet, or that you use as withdrawal address for the bitcoin exchange service.
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This is in the context of Z10, but I suppose meant to apply to all crypto trading...

Is this 2 step process still necessary? Binance, for example has a "Fiat Gateway" where one can purchase bitcoin and other coins with fiat...

Of if not necessary is it still preferred for security, lower cost, or some other reason(s)?

Thanks.