My observation on all of this is that the most common themes to bear Bitcoin - can all be fixed! People are quite happy to look at the current landscape and proclaim immediate and indefinite failure. Detractors allow no room for growth.
Volatility - you could argue that Bitcoin is still so young that the market is trying to determine it's worth. I estimate that Bitcoin is significantly less volatile at some point in the future.
Real world use cases - currently I agree, I don't see a great use of it ... yet. I think we'll find something.
Energy, sure okay it uses a lot of energy. Is this less problematic is most of the energy is sourced from renewables (now or in the future)? Certainly it's also possible that the protocol is updated to be more energy efficient, or another coin reigns supreme.