I put mine on with cold weather in mind... so the first place I went with it was the SW desert areas of the US in early July... I can tell quite a difference in first-sip water difference between mine and my wife's identical setup without the insulated hose (she does not like the cover on the hose for reasons of her own). You are correct that it is not as cool as the water in the reservoir. OTOH, I prefer my water to NOT be icy cold in those conditions - hits the palate and stomach hard on me if it's icy cold. Mostly personal preference, I suppose.

Winter treking made me a belt and suspenders man, so after slaking my thirst in sub-freezing temps, I blow the water out of the tube and back into the reservoir. If the warmer temp water in the hose ever bothered anyone, I suppose that could be done in hot weather as well. I try to NOT blow any air into the reservoir itself, as one of the features I like about a bladder is it makes zero <slosh> noise as long as there is no air in the bladder. Much quieter than a 1/2 empty water bottle. After a little practice, it's pretty easy to gauge how much breath to expel to push the water back without blowing a bubble.

The no-slosh is so great that any auxiliary water bottles I carry are either full or emptied into the bladder. I like things fairly quiet when I'm wandering in the woods.

Tom