Carrying around a tote made of plarn is ok, but some people will give you odd looks. That being said, some of the prettier ones are getting a bit more popular. If you have translucent bags, they make nice totes as long as they're not biodegradable. Biodegradable bags do as the name suggests, biodegrade - good for temporary use.
However - plarn items don't sell as well, I find. Do some research in your area, because I know that different areas can be wildly different in taste - Brighton regular things are very much scoffed at by people in Chelmsford. Hence, you don't see any plarn items in Chelmsford, but in Brighton, there are a few around.
My experience with plarn suggests that items made from it don't always sell, but makes good items.
I made a pair of 'shoes' to walk through the shallows of the beach so that even if there is a pesky stonefish, it wouldn't sting my feet so badly - the padding provided by the double layer of plan on the sole also saved my feet from the stones and shells, and I didn't need to worry about the salt doing damage to the fibres (since plarn is pretty sturdy).
I've made a lot of things with plarn; scrubbers for pans, temporary insoles for my boots, wastepaper baskets, storage bowls, stool seat covers, lunch bags... the list goes on. Basically, anything that I'd use and not care what people say about them because they worked.