I've been doing a very similar approach to Kuyt, I've been doing this for around 3-4 months now in total if I recall correctly. Perhaps longer, anyway I don't think it's the be all and end all but there are a couple of key benefits for me personally:
1) My appetite used to far exceed my daily intake, this was with considerable daily activity. This makes maintaining a good level of bodyfat uncomfortable at the best of times and in the midst of a diet next to impossible. The IF'ing has helped to curb my appetite and need for sugary products considerably.
2) If I get too heavy or eat too much I tend to get sluggish at work. This is something I've only truly appreciated once I've seen the other side of it. As in now I tend to eat light throughout the day I can actually see a large increase in my productivity and general activity throughout the day.
For once I can see this as a dietary approach which would actually be sustainable. Of course the counter-answer is that any diet requires willpower and results come to the person who is willing to refrain from foods that are bad for them. I agree with that, but having this mechanism of appetite control working for you, rather than a diet which leaves you unsatisfied and leaving you hungry for larger meals can only help the process.
The other criticism is that bodybuilders/powerlifters have been eating frequently for years and it has worked just fine. I won't disagree, I'm not so committed to IF or blind to other approaches that I would ignore this, but as a strictly personal preference I like an IF approach far moreso than a regular multi-feed approach.
Another criticism is that there be a loss of muscle. If strength is anything to go by this seems not to be the case, in fact I set a (surprisingly) considerable PR today after a 24 hour fast with 220lbs on the Bench for 20 reps. Bearing in mind I'm natural and relatively experienced this is quite something I think you'd agree. I don't seem to be wasting away.
In the end I like it as just another approach, perhaps one which is friendlier toward an individuals particular circumstances and the friendlier it can be to your life the more likely you will stick to it.