Noob Question On Buying Crypto

Hi. I'm new to Binance and crypto in general, and I have what is probably a very basic question but one that I can't seem to find an answer to and I'm a little confused. I watched some youtube videos and looked at explanations but still...

When you are bying crypto through Binance, what is the right/best way to go about it?

I got really confused at first and deposited some money to my wallet, then I realized I can't figure out how exactly to spend it, so I withdrew it back... (>.<) Later, I bought crypto directly with a debit card but something still bugs me...

When you buy directly with a card, it seems a little more expensive than if you went to the trading screen and bought at lowest current offer. Is this due to the Binance transaction fee? So if you wanted to actually "trade", you would have to first buy BUSD or USDT, at which point the same fee applies? So there's no difference between buying tether and then trading or just buying directly with a card? Other than, when trading you can obviously use the order book.