Not going to disagree that it's hard to take bitcoin seriously, but I don't think that one has ever been much of an issue.
A lot of bitcoin's complexity is rather thinly veiled by the current generation of clients and platforms, but it's basically just a question of time (maybe a lot of time), learnings and improvements until this gets better. Whether bitcoin will survive this period of time is a separate question, but that the complexity can be successfully abstracted away from eventually is inevitable.
It's testament to the quality of the abstractions that cash and credit cards provide that we do trust them and use them without thinking, and wonder how we could ever switch to an alternative system that doesn't offer the same. But there's nothing intrinsically less complex about them, and there's no reason why bitcoin can't get to that point too. Always keep in mind, bitcoin's only been going for a few years - it's an incredibly young technology and ecosystem!
Most people understand that when they swipe their card, dollars are taken out of their account. It's a fairly simple process and pretty easy to understand.
Bitcoin is much more complicated. You need to have files on a hard drive, a wallet, and to send bitcoin, it's non-trivial.
Not to mention all of the crappy insecure websites getting hacked left and right. I know of at least 3 people that bought Bitcoin and lost it all because it was deleted accidentally.
There is also trust there. I run a business using business credit cards and I need to file disputes occasionally. 99.9% of the time, I get my money back with a few phone calls.
This will never happen with Bitcoin.
To make it as easy as a credit card, there needs to be a central authority..which is against the whole premise of Bitcoin.
"Powerful" perhaps. "Reliable" even.
But disdain for big banks and credit card companies is very widespread, and people do want a system that is more... well, responsible.
B. The swings are not 'massive' as you are imagining. The floor at $370 has held through multiple selloffs now. If you look at the Rate of Change per day, it doesn't look much different from the DJIA.
C. The average dollar user doesn't understand how the fed works.
However, I find value in bitcoin because it is relatively independent of inflation and market cycles. Notably, it seems to have an inverse relationship with oppressive currency controls (e.g. greece, venezuela). I suppose, in that way, you could consider it an investment in personal sovereignty.