Ripple co-founder fifth richest person in US, rivaling Zuckerberg

The market cap of Google is 780 billion.

The value under liquidation of Google is (you can find this in their financial reports) ~100 billion. Even that is a vast overestimation of what it would fetch in a firesale, because it's assuming, for example, that with Google firesaling, the ad "inventory" would sell for what it's currently selling for. (There another 70 billion in "intangibles" (guess how much that fetches in a firesale)).

Granted that's pretty high (a company that pays dividends, like Microsoft, it'd be way less, and for insane stocks like Amazon ... let's not go there).

Which do you think reflects the value of Google ? It's an interesting question, and you can if you like get a bachelor, masters or PhD in various ways to answer that question.

But I would say there is no one good answer. Not for XRP, BTC, or for Google, not even for things like the US Dollar.

Ok, so one of the problems things like bitcoin solve is that trust in the currency really encompasses trusting quite a few organisations, and these being trustworthy is only true up to a certain transaction size, and only on large averages. Basically, the issue is that banks can't be trusted, and therefore anyone big enough to make double-digit million value transactions can't be trusted (because they might be the bank, own the bank, or simply owe the bank a lot of money, ...). There are also more complex cases where governments get involved and muck things up (financial fraud, bankruptcy cases, tax investigations, ...). And there are other cases (terrorist financing, sanctions, ...).

All of those problems should not be the concern of merchants, but they are in practice, because governments have unilaterally decided that interfering without recourse in payment systems is the way they'll police the world. So they change payment streams (which are between 2 parties, say A and B, and they have some problem with A). Issue is always the same: B buys something from A. One of the parties in the chain, or a government, or the police, or ... has a bill for A, and halts the payment. A then claims (truthfully) non-reception of funds and refuses to deliver. B is left without recourse, without money, and without the good they paid for. Needless to say, nobody accepts responsibility for damaging B. But it gets worse.

So in fact this is one of the big advantages of cryptocurrencies, actually. With dollars (or any such currency), even if they're on your bank account they can disappear months later.

Essentially, large banks, judicial system and governments have the ability to impose their losses on others, in the "traditional" currency systems, and they use that ability too much, without caring who else they damage in the process.

When it comes to "if I have the money, I can trust that I actually have it" cryptocurrencies (all of them) are far superior to SWIFT (essentially all banks are part of SWIFT) in terms of what merchants consider trustworthiness.

There are other advantages that they also have. For instance, despite the complaints, bitcoin is still far faster than SWIFT.

It doesn't seem that difficult to cash out at least few billion with that kind of volume.

What? Where on earth did you get that? Because his girlfriend bought one for $10 from the story, you've now created the idea that she did the math, considers it a worthy investment and knows the full market cap? What if she just wanted $10 of entertainment for the evening by buying a silly coin and talking about it? That seems like a solid investment to me, much cheaper than a movie for example, and does not imply that she thinks the full value is worth $10T USD. She could easily be a rational investor who thinks no such thing.

A market composed of numerous entities trading large sums of money is a much better system to decide the price of something. One person making a single purchase for unknown reasons is not a "market".