Bitcoin is main cryptocurrencyon the motion of which all are guided. I think, that can invest in bitcoin and all top crypto-currencies, because are at the beginning of long journey, but the main thing is not to expect a quick income from them.And it's an investment and need a lot of time to get profit. And the main thing is invest free and non-debt money.
My opinion about this topic is that bitcoin investment is more risky thing compared to typical investment for instance bank investment which I think safer than it. But along with the risks involved in bitcoin investment it offers higher profit in return.