Presuming room temperature isn’t, like, 70+ degrees and it’s sitting there most of the day, no problem. Keeping pre-mixed Mag-10 bedside is pretty common and it’s what more than a few people do. Don’t worry about it. Ha, I actually throw one down right before bed since I get up enough to pee no matter what.
“Need”? Nope, not really. The protein efficiency of hydrolyzed casein is much higher than most other protein sources, so even though it’s “only” 20g protein per serving, your body is putting more of it to use so it can have a much stronger impact than a larger serving of whey or some other shake. This article does explain the what, when, and why for using different types of protein.
I do still keep Metabolic Drive on hand to make protein pancakes and whatnot. And sometimes you just get in the mood for a icy blender bomb with chocolate Metabolic Drive, a spoon of peanut butter, and half a banana. MD works perfect for those.