Might to a marketing ploy. It is possibly remnds me of shampoo bottles that recommend the same brand conditioner on the label.
My understanding is the detergent and rinse aids are added to different cycles (detergent to wash cycle…rinse aid to rinse cycle). They would not interact with each other as the cycles are different…thus, a detergent brand won’t have any impact on a rinse aid brand.
Notwithstanding this, with the newer 5 or 10 in one tablets, some of these contain rinse aids which may negate the need for a separate rinse aid…I see that even for these tablets, rinse aids are still recommended for conditions where water has high salt (TDS) content. In such case where an additional rinse aid is required, the above would apply.
I can see matching a rinse aid with water quality used in the dishwasher…namely using one that is found to work better in assisting drying with the water quality in one’s home. Such would not be brand specific (same as detergent) and could be different to the detergent brands if it performs well.