I typed a long response, but accidentaly hit back and lost it
Medulant and hedkikr made great points on the training value in broken tempo: breath regulation, timing etc.
I will say this though:
Modern kata performances have excessive, dramatic pauses mid-technique. This is unnecessary. These static, deadlocked positions are a result of the problem in transmission of karate to Japan and to the USA. This was furthered as time went on for sake of aesthetics. Dynamic, continuous body motion should never be sacrificed for the sake of visually pleasing broken rythm.