The problem with DVR footage from your goggles is that there is usually a good amount of noise and flickering that is also being recorded onto your footage. This tiny 5g module circumvents all of that radio interference from your VTX and VRX by recording directly from your FPV camera! There might be other onboard DVR's larger and record in a higher resolution, but you won't find a smaller and lighter DVR that you can fit on anything, even whoops.
This is perfect for those who fly tiny or ultralight builds without an action camera such as a GoPro and want to review their footage in higher quality than a goggle DVR can.