First of all, BITCOIN IS NOT MADE TO REPLACE MONEY.
It has a set number of created or 'minted' coin, 21million. That immediately tells you that there will never be enough Bitcoin to ever be used as a transaction coin.
Not only is it they're not enough to use it as a transaction coin, but it wasn't designed as a transaction coin, therefore it has extremely high rates to send the coin.
Ergo, an ASSET coin.
There are cryptocurrencies however that are specifically designed to be transaction coins. No one cryptocurrency though could ever hope to replace fiat cash, because the value of having physical over digital is never going to be outweighed. The only value in a cryptocurrency they're truly is the value the users give it, in the value in which the encryption and the limited supply of the coin provide.
If you think of them more as specialized game currencies, and they are only used within a platform, but it can be used like real money.
Now we do know criminals are using this TRANSPARENT LEDGER, AND NO AMOUNT OF FUNDS SHUFFLING CAN HIDE THAT YOU ARE MOVING MONEY. THEY WILL BE CAUGHT INEVITABLY, THERE IS NO WAY ATOUND THAT. Cryptos that are made to hide the ledger, I know less about, but since all transactions have to exist in some sort of network where everything is being recorded, no bit of information is ever technically inaccessible.
Banks made Ripple. Bitcoins' creator is anon, and has never surfaced. Anyone could try to take that claim to fame, but there is evidence and records in forums about the creator, and conversations with the creator about its purpose which is to show that money could be decentralized.
Right now, miners all over the world have been COMPETING with CHINA to make sure they never gain 51% of the network! THEY COULD THEN CHANGE BITCOIN HOW EVER WAY THEY WANT!
Bitcoin is an open source project that can only have changes made when people agree on them! If you want to voice a change, you presented to the community, and it's up to the community to transfer over to that, if you fail to have 51% of the community follow after, that means you create a fork of the coin instead and it's value could be nothing.
I will do the best to answer questions, but I spent my time search Bitcon and cryptos in 2017, so I could be a smidge out of date with other replies, but what I say in this particular post is the core of most crypto and Bitcoin discussion in the crypto communities.
Never in it's entirety. Realize that's a weird thing to skip....and I just never circled back. Probably should.