I own a Burley flatbed and use my kayak dry bags to store my gear. Works great. If you are B&B touring, then I would not use it, no need. In fact I would only use small panniers for that type of riding. This type of trailer compacts quickly(QR wheels and tow bar) and I think (tho never tried) it might fit in a bike box with the bike. Price...cost me 100.00 new(end of year clearance). I don't think you can find decent panniers and racks at that cost. My main complaint is when I walk through town it clogs up the sidewalk. So I just lock it up and walk w/o my stuff.
A trailer allows for some gear swapping allowing one person to ride 'free' for 1/2 the trip. On a recent tour I carried everything and my buddy carried nothing. It was easy. We were gonna swap but I didn't feel the need. Just another option.