So here's another issue: The usage of the investors can affect the spenders' side negatively, but not the opposite. The fact that it's seen more speculatively affects those who want to use it as a currency. This is what, after all, makes it difficult to achieve adoption in a global level.
Yeah but only to some extent and it somewhat depends on your views. The investors and specifically traders affect volatility.
* There is one hardcore bitcoin view that sees it as a currency that provides financial sovereignty and people with this view don't care about the price fluctuations at all.
* Another more mellow view is those who spend bitcoin while enjoying the increase in their purchasing power. For example you have $100 and park it in bitcoin then after some months you have $200 to spend. Who doesn't like that?
This is why despite all the slow adoption we are still seeing great progress in adoption to the point that I have even seen restaurants that accept bitcoin payment in where I live!