I've got a "low gravity" bicycle, but it's not a Worksman. I've got a couple of Worksman bicycles, but not the low-gravity model.
I think it would be great for the right application. Several things to keep in mind, though. One is that the basic model is single-speed and coaster-brake. That means it'll work great where it's flat. If you live in hilly country, you may be looking at gearing and braking upgrades. I've read that it's heavy. There again, on flat land, no problem. It's a one-size-fits-all frame (though they do have a lady's frame as well, I think). Meaning, if you're average size, you're probably okay. If you're very tall, you may run into problems with it.
In general, the Worksman bikes tend to be decently made and decently priced. They are low-tech, and not that different from what you'd see on a Schwinn from 40 years ago. The wheels are heavily built, and one of the strong points of the bikes. I would like to have one of the low-gravity models, though I can't quite justify the cost at the moment. If I ever see a used one in the area, I'll snap it up, though.
Watch the freight cost, as they may cost more to ship than a standard cruiser, due to the bulky/heavy basket. If you're planning to put rear baskets on it, check about buying them at the same time- they may can ship them cheaper (inside the front basket) than ordering them seperately.
It seems to me that for moderate shopping, they'd work better than a longtail, as you can just throw the junk in the basket. I doubt you could get a full grocery cart in one, though- that pretty well loads up my front-loading tricycle. They cost around $500 or $600, but don't expect a $2,600 bike out of the deal, either.
One minor drawback with my low-gravity bike is that when you get the front basket loaded pretty heavily, you can no longer pick the front wheel up by lifting the handlebars- the rear wheel will raise instead. Meaning, it's a bit more awkward to lift it up over a curb than a standard bicycle. Figure that when you're riding one of these loaded, you're not going to be going too fast. So a couple of miles to the store would be great, but riding 15 miles into town and back might be a stretch. That big basket does catch wind, too.
By the way, Schwinn made a similar model from about 1938 to 1968 or so, which they called a "cycle truck". When searching Ebay or Craigslist, included that term as well. The Schwinn models are collector's items and so are overpriced for users, but you'll find the Worksman bikes called "cycle trucks", too.