Regarding altcoins, I’ve been thinking about privacy for a long time, and then I stumbled upon this rant, which sums it up nicely:
In short, Bitcoin and Ethereum are not truly private. The most popular truly private option is Monero. Now think about it: when push comes to shove, will people want to hold a crypto currency, which ownership thereof can be traced back to them? The allure of physical gold is that you can just hide it and nobody will know you have it. This is not true for Bitcoin.