Altcoin are a riskier investment but potentially much more profitable (i you find the right ones and with an favourable overall market). The problem is there are too many of them, investors are too divided (and many are useless except for speculation).

On the other hand at the technology level some surpass BTC in many domains (if we look only transfer speeds and costs, BTC is obsolete)
For the moment it's mainly speculation side that's at play, I have the feeling that projects are taking second place