Next to Bitcoins there are several different other crypto currencies like DASH, ETC, ETHEREUM, LTC, XRP. Do you believe in them? Are there any Advantages and/or disadvantages?

yes I do believe in them, many good projects are under other crypto currencies. Some crypto currencies are also good investments but be very careful, some are scams, better do research before investing. And also another reason for believing in other crypto currencies is that they offer services that bitcoin doesn't offer. Crypto currencies has it own advantages and disadvantages you just need to know or use them according to what you need.
There are lots of advantages in having cryptos. They have specific objectives depending on their project and if we got that successful tojen. We have the privileged to have says on that project.