My credit card pays me 2% to use it.
If there’s a problem with my transaction, I click some buttons and the card company reversed the charges.
If I lose my card, I call them up and get another one overnight without losing all my money.
Why would I give all of that up, pay exchange fees on both ends of a transaction, pay transaction fees (however small), and wait longer for my transactions to clear?
Why do we need to invent an all-new alternative currency and asset class just to use these technologies? Why do I have to invest in 1 of 1000s of altcoins just to arbitrary change numbers in a shared ledger?
This is not even some dispited facts (that this is one of major reasons for why some people want a new currency), this thing has been discussed over and over into oblivion, since the beginning of cryptocurrencies. It is a question that has been answered millions of times at this point. You just haven't researched any of it.
I'm not necessarily saying this system is better or worse than some alternative, just pointing out that it's not all upside.