The tagline for the sleeping pad category is "Find the best backpacking and camping sleeping pads for comfort and support. NEMO sleeping pads are lightweight, packable, and built for your next adventure." Comfort is definitely a concern.

The pads do list their insulation value, but so do non-ultralight sleeping pads.

The reason is that the insulation value is incredibly important to comfort. From experience, a sleeping mat that is thick, but with bad insulation will lead to a way less comfortable night than a thin one with good insulation.

Sleeping bags don't provide much insulation on the bottom because they are compressed under your body (the insulation from a sleeping bag typically comes from air trapped in the fill). Any insulation between you and the cold ground has to come from the sleeping mat. That's why it is important to get one that is cushioned enough for your body as well as being insulated enough.

R values aren't an ultralight camper thing, they are an informed camper thing.