The Sea to Summit website describes the Traveller sleeping bag as follows: "This aptly named sleeping bag and down blanket is the traveler's best friend. Whether you are on a summer bike tour, or a hut trip, or couch surfing, or simply stuck at an airport or ferry terminal, the Traveller unpacks from an almost impossibly small compression sack to reveal a rectangular sleeping bag which can also unzip to form a quilt."
Using two sleeping bags is how my wife and I sleep in our camper. This provides us with individual flexibility during the night to regulate our warmth. Our older Traveller bags were advertised as good down to 45 degrees. The new bags on the website can be bought for 30-degree and 50-degree tolerances. We have bags for colder weather and usually take them along with us in cold-weather camping for emergencies, but we've found that our 45-degree bags are usually fine inside a trailer with a heater. If we get a little cold, we usually bring along an extra blanket later in the camping season. We do like how the bag can either be used as a bag or a quilt.
One thing that is also good is that the bags come with both a compression bag and a storage cell. The compression bag squeezes the sleeping bag down into a really small size; however, we have always used the storage cell--a zip bag roughly a foot by eight by five inches. The bag is tucked away much more quickly, doesn't need time to decompress, and can actually function as a pillow for the back when we are sitting in the little camper to read or type, for instance.
A Sea to Summit blog article explains the versatility of the bag pretty well. I have packed the bag into its compression sack and then taken it while traveling by plane, using the bag in a motel room. I've also used the bag on Amtrak when traveling the Zephyr route over the Rockies in the winter. Mostly, though, the Traveller allows my wife and me to avoid SOS (sleeping bag overkill syndrome), or in other words, we don't get too hot when we use the bag. I usually use my bag unzipped as a quilt. My wife keeps the end slightly zipped up so that she can keep her feet warm in the little end pocket the bottom zipping provides. Her method also lends itself to sliding into the bag and zipping up if it gets cool during the night.
I can speak mostly for my bag, which has held up well over the years--bike camping, tenting, and also tiny trailer camping. Sometimes I've even used the bag on the sofa while watching TV. I wash and dry the bag at home; it's held up well with no rips or zipper malfunctions.
Even in small travel trailers, some folks like to make up a bed and keep it made all the time. We regularly convert our bed to a bench/table configuration during the day for either work or meals, so having these bags which quickly stuff into their storage cells are for us a convenient solution for converting our tiny trailer space for different activities. Based on our experience, these sleeping bags have been practical and reliable. They've helped to make getting ready for bed at night a no-fuss experience. When we think about our sleeping bags, we usually have warm (but not too warm!) thoughts. Sleep long and prosper, fellow campers!