Metta towards yourself - useless?

There is a part of Yuttadhammo's answer at [How to practice Metta without a Benefactor?](https://buddhism.stackexchange.com/questions/7865/how-to-practice-metta-without-a-benefactor?rq=1) that has very confused me: > cultivate metta towards yourself **(useless, but a good example)** Why is metta useless? Are there any specific sources for this statement, or is this based on a determine school?