Put it this way, if someone walking by steals your CC info, (not how it works, but I will use your example in this case) you are only liable for a maximum of $50 to the CC company, if you are using a CC.
If the same thing happens with your debit card, you are liable for any amount they are able to charge before caught. Some banks are better with security, and some are better at covering some fraud. But if push comes to shove, they do not have to cover anything, and you are liable for everything. In many cases if they dont catch it, once the money is deducted from your account you are SOL, and that money is just gone. At that point they will stop any new charges but anything already done, is gone. Meaning whatever limit on purchases you might have might be your only saving grace but if that is $500 a day, and you catch it the first day, you still are out 10x what you would be out if it was a CC. Hell they could charge up $100K on your CC and you still would only be liable for $50.
That is just the way it is, then you take the perks of using CCs, cash back, miles, a significant bump to your credit rating, (not having any CCs significantly hurts your credit number. )
If you spend $100 dollars on your debit card, you just spent $100.
If you spend $100 dollars on your CC you, spent the $100, but depending on the card etc. could get cash back, you could get miles, you could get other bonuses to use towards future purchases. Plus other discounts and perks when using your CC, in most cases.
I could literally buy a few thousand dollars worth of stuff on amazon and use nothing but miles if I chose to, hell I can use them in a ton of places if I want. But I would rather save the miles and use them on a trip.