Altcoins are basically useless except for demonstrating/testing out new ideas or perhaps as a fork if Bitcoin got too corrupted.
Which comes from someone who does not make money from alts because if he did he would know they are more than useless and they in fact a money maker. You are right about them being good for testing out new ideas etc but one of these will creep up before you know it, can't put a lid on better tech for long.