I have a used HTT with enclosed underbelly.
When I bought the camper, I thought nothing about it. I thought only about summer camping.
This year I used the camper to go to Florida.
Since I live in Western New York, I towed the camper to Kentucky to store until January so I did not have to tow in snowy conditions. I winterized it first.
When I picked it up in Kentucky we spent a night camping in below freezing temperatures. The next night in Georgia freezing temps again. Several nights after that near freezing temps in north Florida.
I never in a thousand years would have expected to use my camper in those conditions - but I am typing this message from those conditions now.
I am certainly glad the previous owner had this camper's underbelly enclosed.
Caryl - from chilly, sunny, Florida
PS - Yes, I did have to do work to a water line last summer and will have to do some work under the camper next summer (myself) and STILL appreciate the enclosed underbelly.