Well, you just said that's he's wrong. One "killer application" is that it's a "stable" store of value. Not perfectly stable, it can quickly fall by a factor of about 2, and if you buy in the worst bubble it might fall to a fourth of its value. That's decidedly less stable than Western currencies, but it's more stable than some others. And for many people Bitcoin is more accessible than the foreign exchange market. It also tends to rise in value over sufficiently long time scales.
The other use is providing online payments to people who aren't in the banking system. The banking system requires trust, and shuts untrustworthy people out - both at the level of individuals and entire regions. Bitcoin eliminates the need for trust (on the monetary layer) and can thus reach more people.
Both are great applications. They are largely irrelevant in the West because only a tiny fraction of us experience those problems, but that doesn't mean they don't exist elsewhere.
So, it’s stable as long as you understand it is unstable, and helps people without access to banking but with a stable, constant internet connection and perfect operational security, access none of the benefits of having a bank account.
Oh, and it’s actually neither of those but if you wish _reaaaaly_ hard and ignore all the practical problems, it might be, someday.
In absolute terms it's not stable, in relative terms it can be. If you gave me the choice between storing my money in Bitcoin or Turkish Lira I would choose Bitcoin every time. If I have the option to use USD instead the answer is different.
> helps people without access to banking but with a stable, constant internet connection and perfect operational security
You don't need constant internet connection unless you are mining or want to verify a payment right now. And mobile internet and smartphones are surprisingly prevalent in the third world (and among homeless in the first world).
But it’s still a store of value. No store of value is perfect, USD will lose value over time to inflation, stock indices are subject to volatility, gold is subject to theft and volatility, other foreign currencies are subject to government corruption and hyper inflation, fine art is subject to fraud and damage, etc.
So as a store of value Bitcoin actually has a good track record and is trending towards lower volatility as adoption grows.
People really need to stop thinking in absolute terms regarding value storage. It’s analogous to energy storage. Batteries leak energy over time, but we don’t sit around yelling about how they are not stores of energy.
The other use is providing online payments to people who aren't in the banking system. The banking system requires trust, and shuts untrustworthy people out - both at the level of individuals and entire regions. Bitcoin eliminates the need for trust (on the monetary layer) and can thus reach more people.
Both are great applications. They are largely irrelevant in the West because only a tiny fraction of us experience those problems, but that doesn't mean they don't exist elsewhere.