"I did X because I wanted to do X" is not a meaningful motive unless X is intrinsically pleasurable.

I disagree. Sure, "I did X because I wanted to do X" is incomplete as an explanation, if you don't also add what makes you want to do X (intrinsic pleasure, a sense of duty/morals, a promise of better financial prospects or better health, etc.) Alicorn's statement is comparable to "by default, one does not exercise (true for most people), and I wanted to be fitter and healthier, so I pre-committed by signing up for a weekly yoga class." Would you agree that it was a meaningful statement if she had said "I wanted to have the benefits of having signed up"?