They’re not elastic, just a draw string, like BOA but without the dial.
I’ve got the ‘artic’ version which has an extra fluffy/faux fur type lining. Never had cold toes, they get used for wet rides all year, just change from thin socks in the summer to full on winter socks when it gets below -5 🙂
I wouldn’t agree on the ‘stiff’ comment though, they’re not floppy like DX/MP66 shimano’s, but they’re a lot softer than summer disco slippers. Just the right ammount though IME, not soft enough to make SPD’s uncomfortable after all day rides, but just enough flex to allow walking short distances.
I’ve ended up with wet feet a couple of times, but they were rare occasions, and I didn’t actualy notice untill I got back to the car and had to change into trainers as they stayed warm. Those rides involved river crossings though.