ASCOM drivers tend to be fairly simple, all they do is convert commands using the ASCOM specification to commands to a device specific driver. This is known as a façade. This is particularly the case with cameras where all that’s needed is to communicate with a camera specific driver.
Direct control from SGP does the same thing, the SGP direct control driver connects to the same camera device driver and sends the same commands. Most of the complexity should be in the camera driver or SGP.
What this means if that direct control may make very little difference. For the most part the same software is used so if there are problems they will still be there.
Using two cameras at the same time is another can of worms. The camera control software has to be written to allow for this at all levels, from the camera drivers, through the ASCOM (or direct) interface. I’ve done ASCOM drivers for a couple of cameras and it’s not at all easy.