I will play devils advocate here...only because I hate timing my sets UNLESS it is a single rest pause set then I have to in order to ensure I am comparing apples to apples for purposes of progression. I am not saying it is not beneficial, I am just saying I find it distasteful as I expressed earlier (feel like I am more focused on the clock than the execution of the exercise).
It is a generally accepted belief that mechanical tension is the primary driver of hypertrophy. Other contributors include muscle damage and metabolic stress along with volume. So here is my question. If I am chasing these big factors for hypertrophy would it not be more beneficial to take more time between sets to allow for a greater load. For example: If I did the 10x10 protocol as described above with 15 seconds rest I might hypothetically use 150 lbs. for a total volume number of 15,000. If I did that same 10x10 and allowed 2 minutes rest between sets I might be able to use 200 lbs. for a total volume of 20,000. Under scenario 1 I used a max mechanical tension of 150 and a total volume load of 15,000. Under scenario 2 I used a max mechanical tension of 200 and a total volume load of 20,000. On face value, the only benefit to scenario 1 would be for cardiovascular training and obviously it is less time consuming. But for muscle building it was appear scenario 2 was far more beneficial as it impacted the hypertrophy factors much more intensely than scenario 1.
Like I said, I could be way wrong here. Heck if short rest periods are proven to be superior to longer rest periods I would do it in a heartbeat. But on face value, it seems less advantageous to use this approach if you are trying to build muscle.