The guys love to hang around in theirs. I think to a degree they feel a little safer having an area off the ground to shoot too when i accidentally scare them - at least for mine. If i open the lid to their tubs they could run to hide in their caves, under the kitchen roll or in the tube and they almost always choose the tube. Its probably because its the darkest and most enclosed.
Lapsang likes to hang half in half out of hers.
Oolong has started trying to drag mice into his when he eats - usually fails because he can't lift them that high, but occasionally succeeds and i just change the tube later on. I gave him this mouse on the floor of his tub and left him too it - checked on him after a few minutes and found this little sight!