How important is the INT pin of the MPU6050 (GY-521)? I want to wire multiple MPU6050 (at least 16 of them) to an arduino UNO for development (then nano for production). So I first started wiring one MPU6050 to an arduino like shown on the diyhacking website or in the picture below:

as you can see in the picture above the INT pin is used.
I then wearched for a way to wire multiple MPU6050 to an arduino using a multiplexer and I found a way on horizonlab's website or see the picture below:

As you can see in the second picture the INT isn't used at all. I'd like to know how important it is and what I'm missing out by not using it.
The INT is the interrupt signal, usually open-drain output and you can connect many of them to the single MCU interrupt line (but you have to check all devices which ones are ready). The LOW level from MPU device signalize that data are ready (conversion was finished). So you don't have to periodically read status register to find it out (no polling is necessary).

In short, using INT is optional.