Here is Shimano's explanation of how the front shifting is designed to improve shifting. This is from the very beginning of SG-X so some differences have been made since. MTB triple in this example.



It includes pins (or hook, plates,...) on the inner side of the chainrings (opposite of the blue arrows) to pickup the chain to move it to larger rings.

Additionally, the rings are 'clocked' relative to each other so the distance between teeth on 'matching' rings is spaced such that the chain can engage easily, without riding on the tip of the teeth.

Other design elements are shaping of the teeth to release or pickup the chain, as applicable.

So, essentially using rings that are not designed to be 'paired' may have an effect on shifting. How much? ...