Scam? i dont think so, etherum is one of the very best projects, with the largest number of markets after bitcoin. they are not scam

At the moment bank is probably safer, but here is a huge but. I am not a big fan of any bank. They are in an unequal power position compared to a regular consumer. For me, this is not so much about safety than changing the commerce world to more consumer-friendly in the future.

You should never sell your coins at a lower price than you bought them for because that is how you make losses.

Hold your coins. You should never sell your coins at a lower price than you bought them for because that is how you make losses. Although I cannot tell you that the coins will not fall lower for sure, what I can tell you is that the price cannot stay down forever and it will definitely recover and you will make all your money back.

Some altcoins show a good price increase and therefore investing in them can give a lot more profit than buying bitcoin.

Not everything, but exactly more than half that's for sure. Think where to invest.