Whilst modern dishwasher detergents can take advantage of wash temperatures of 104°F (40°C) and in the vicinity, the biggest issue people are likely to have at that sort of temperature is GREASE not being put into suspension correctly. 

Most detergent enzymes have been modified to allow them to operate up to much hotter temperatures, where they can survive and still provide more than adequate cleaning power with grease in suspension. 

Personally, I am not a fan of the colder cycles on dishwashers. We simply have too much grease on our plates to wash at such cool temperatures, and I've found (even with Phosphated Finish Powders/Tablets and other detergents) that even 50° is not enough to keep the dishwasher filter clean in the long-term. You slowly get a layer of slime buildup on the filters. All the water is washed through that. 

Washing at hotter temperatures completely suspends such "crap" and prevents it adhering to the filters - but I am stuck between wasting time and energy at hot temperatures (like >140F/60C) and not cleaning filters, or washing cooler and cleaning filters. 

Part of the problem is also the lack of Pre-Washes on Non-US model DishDrawers about 3 years old, like mine. 

So unless your dishwasher has a disposer blade, self-cleaning filters, then I cannot recommend cooler temperatures. I CAN recommend the Auto cycles, since they generally can wash very hot, or not as hot, and your soil levels interchange the amount of washing and rinsing you get. Thankfully, it means you don't have to 'remember' to add in several heavy cycles weekly to get clean filters, like me :)