As to why people continue to purchase them, here is my personal situation:
1) I have taught many people to shoot, and I like to work them up gradually from 22, to 32, to a low-recoiling 380, and so on and so forth.
2) I shoot at the range quite often and like to shoot a variety of calibers.
3) My FiL reloads 380acp for both of us.
Due to these factors, I find duty-sized 380acp pistols to be quite useful. They fill a good niche for me.
I already had an excellent 380 Makarov, Beretta 84, and Colt Government 380. My FiL bought a CZ83. After I shot it a few times I had to admit that as far as ergonomics, aaccuracy, fitting my hand, pointability, etc, it was a better 380 pistol for me to shoot at the range than any of my other 380's. So I bought one. CDI Sales had a bunch, ranging in price from $235 to $315. I paid $315 for one that looked practically unfired. For a pistol of its quality, that is a steal!
I am not at all denigrating my other large 380 pistols. They are all very good. In fact, due to its locked breech, I will continue to encourage any future beginners (and my recoil-shy daughter) to use my Colt Government Model, which is a sweet pistol indeed.
But when my FiL and I shoot at our regular 15-yard distance, the CZ83 is the best 380 pistol for me. All in all, that's why I bought it. I didn't purchase it with SD in mind, though I would certainly not feel unarmed with it. I view it as a very nice range toy at an excellent price. I would imagine that many others have them for similar reasons.