[I'm not particularly pro or anti cryptocurrency--having a strong opinion on this strikes me as odd. But a few things in your post seem worth noting.]
> I hope you will research some more.
This is sort of a snarky way to start a post. :) Maybe they know something you don't know?
> Cryptocurrency is about democratization of money.
I never can figure out what this means. By some point of view, all money is democratic; it only has value if other people assign it value, and it has value roughly in proportion to how much value people assign it.
This is extremely democratic!
(Arguably, if you're a chartalist, then most "fiat" currency only has value because governments assign it value, but I think this is a bit of a silly perspective; even if it is true, it's like saying "when you cast your vote, it only has value because governments assign it value", which, like, yes? That's the point? But also, strict chartalism doesn't really make a lot of sense; people are often keen to buy Swiss Francs even though the tax base for Francs is quite small, after all.)
> Removing intermediaries for holding and exchanging money digitally.
I don't think this has anything to do with the definition of "democratic." Maybe you mean disintermediated? Grassroots? Distributed? But none of those adjectives suggest quite the normative value that "democratic" does. Why do I care if my money is disintermediated?
> The typical way for digital monetary exchange is a credit card transaction, which is completely obsolete.
"Obsolete" is an odd way to describe something used by hundreds of millions or billions of people on a regular basis.
> It's like giving away the key to your cryptocurrency wallet every time you make a transaction.
This is perhaps your least well-founded statement.
First, it isn't: if you give away your cryptocurrency wallet, anyone can steal your money without recourse. But if I give you my credit card number--which I'm not inclined to do, I admit--the worst case is I have to call my credit card company and get a new number. This is wildly different than the cryptocurrency analogy.
(Now, it is true that all that fraud detection, insurance, chargebacks, etc, are all paid for, directly or indirectly, by transaction fees. But the average BTC transaction fee is about $8, which would be break-even with a ~2% credit card transaction fee when the transaction exceeds $400--not very efficient either, and with far fewer consumer protections!)
But more to the point, and what strikes me as especially ludicrous about your argument: every time you do a transaction online, be it with BTC or Visa, what do you do? You go to a site with "https". Who are you trusting to help you validate that HTTPS identity? Some certificate authority.
Bitcoin doesn't exist in a "zero trust" world. There's no such thing. I do think shipping around static credit card numbers is kind of bad, and we're gradually seeing more secure replacements (EMV in the real world, online systems like Apple Pay in the virtual). But the idea that cryptocurrency is somehow immune to this reliance on trusted third parties is just wrong, and the suggestion that for practical usage it's actually better for consumers is just laughable.
I do disagree with the parent poster--cryptocurrencies serve a (currently) legal and (in most social systems) "legit" purpose: as a store of wealth and speculative asset. But they don't serve as the basis for regular consumer transactions, because most cryptocurrencies are just really bad for that.