That was actually my point. What I was saying is that the problem with balancing for "power" is that it can be defined entirely too narrowly. The use of that word brings to mind things that both change depending on what game you are playing, and depending on who you ask. some people only look at power in terms of how much damage you can do(cough, cough, D&D, cough) and others look at it in a much more broad spectrum. Note, I wasn't actually disagreeing, so much as saying that I thought your phrasing was limiting in and to some extent detracted from the point.
Honestly, I've found that point buy systems are either the most broken, or the most balanced games, simply because depending on the rules they use to limit high level abilities, (and the game itself) a character who is focused on one aspect(say, damage) is going to be just as useful in game(which really should be the metric) as a character who is much more broad based. However, if the limits are poor, poorly thought out, or the game rewards one aspect of the character more than others(which is, admittedly, often more in the hands of the GM than anything) then the become broken very quickly.