Where on earth did you get that figure of 97% from!! It's actually around 40% of power required is to overcome air resistance. It has been shown in proper test conditions that ceramic bearings DO make a realistic difference. The choice that has to be made though, is whether or not you feel that the significantly increased expense is justified by your own specific needs. For example, in this years 10 mile National Time Trial, Matt Bottrill won by 2 seconds from Ryan Mullen. If it were that Bottrill uses Ceramic and Mullen doesn't, then the expense is totally justified. Do you see my point? I accept that this is an extreme example but if it means that a couple of seconds in a '10' can be the difference between winning or losing, beating a PB or maybe getting under the magic 20 min' mark then it's worth it - every time! Simple answer is, if you can afford it then do it.
Graham