I’d definitely agree, solid ground and a tent would make putting them in the sleeping bag a bit less important (plus then you can use them as a pillow). Having them in our bag was just something I was taught in basic training and it worked well the few times I have woken up with frost or ice on my outer shell (all Army related “camping”).

In the decades since I’ve slowly shifted from big tents to a small travel trailer, it’s so much better on my joints lol.