Several users has described the major difference that's the virtual usage. It cannot be used same as our fiat currency. It requires some basic understanding for using it as everything is linked to technology and internet. Real money is simple that even an uneducated man can use without difficulty.
I agree, some people will even say bitcoin is illegal because it comes from the deepweb. But for those people that are technology literate, they will always know bitcoin and how it works. People around me don't know anything at all about bitcoin, they just know i earn online and the money i earn were always sent to my bank account.
And they would just stop their research there and forever believe that bitcoin is illegal. They'll think that the reason why you are earning good amount of money because you're doing some shady activities on the Internet. People will look at you and think of you as someone who has some weird job that can only be done online.
But, we don't really need those people. Stop enlightening this type of people. Let them believe what they are already believing because after you explained everything about bitcoin, they will still think that it's illegal. They only hear what they want to hear. And if you explain bitcoins to them, they'd just think you're being defensive.