I can understand the 'Don't waste an IOT pilot slot' and the 'You're not committed enough' viewpoints. But really, you have little to lose. You won't get through IOT, pilot training and make it to a front line squadron unless you are 100% committed but you might find, when surrounded and encouraged by others in the same position, that you do have that desire.
Worst that can happen is that you bang out at some stage. There would be no shame in that and you can head off and do your PhD then. A year or so lost in your 20s is nothing.
I went through OASC in the early 90s and failed pilot selection on eyesight but was offered nav. I decided I didn't want to sit behind/next to someone doing the job I really wanted, but there have been times over the years when I wonder whether should I have given it more consideration.
Be selfish and think about what you could be turning down.