4.Ease of use[/size]-Bitcoin is much harder and more complicated than holding cash. people need to learn how to take responsibility for the private keys that control their bitcoin.
this is the only valid point you can make. although the wallets are very easy to use nowadays. from centralized custodial ones that look like PayPal to secure desktop wallets that are easy to use such as Electrum.
The "Ease of use" is really the only acceptable problem of bitcoin here. However, I think OP is talking more about the image bitcoin has in the average Joe's mind. It is a problem too. Few are scared and hesitant to try bitcoin because they only knew it as a platform they can't fully trust. We can root it because of bitcoin's history. Silk road and Mt. Gox issues for example. Even films with bitcoins only use it for illegal transactions. The image of bitcoin for them isn't that good. So whenever there's a problem about hacking etc, they always associate it with bitcoin. It's an image problem.
So I think we have to solve it too, how can we make people trust bitcoin. It's like a problem in branding a product or a person. But not a problem in the product itself. We have to spread knowledge about the true nature of bitcoin, not just a platform for hacking and illegal transactions.