What do you think miners are doing? And with ICOs you can literally just print however many you want.
> I see BTC as being no different to trading stocks, some days you lose and some days you win.
Sure, but with stocks there's usually a company actually doing something.
It's lost work though, and the amount of work is governed only by the level of competition with other miners, rather than the amount of effort involved insome external task.
> Jpm can/does create wealth by moving figures around on reports, or by betting one asset against another, without any physical limitation on its actions.
That's somewhat beside the point.
It's the cost of securing the network. It's not lost. Fees and rewards pay the miners for the cost of their computing cycles, to provide a secure, very difficult (near impossible) to attack network.
And it's still not an external task, it's a facet of running the currency rather than work that is independently useful.
And it's still conjuring money out of nothing.