Some of these mirrors have a straight stick and some have a bent one and no one selling them seems to be able to tell me why I would choose one over the other.
Before I discovered the joys of spending NASA money on Zefal and B&M, I shopped at my LBS, who was eighty years old and from the blacksmith age of bicycle mechanics. He kept only one all-purpose mirror, and I used them for ten or twelve years, until I became a sophisticate. They were quite literally truck mirrors, meant to bolt into the doors of trucks with hinges that stuck out, and to replace the hinge pin. He carried a crude bent steel bracket to attach this
thing to the handlebars. The long stem was bent so that you could mount it inboard and from there it would rise gracefully so that it looked backwards past your upper arm and you didn't have to drop your eyes very far.
The bike I fitted it to I bought by telling this old blacksmith, "Get the importer of the best bikes here so I can see his eyes when he lies to me." When the MD appeared, I asked him what was the best bike he had unsold for more than a year because it was overpriced, and after he told me the price, I clutched at my heart and offered him half. It was unsold because it was purple, so he took the deal. When he saw this clunking great big truck mirror the LBS fitted to Peugeot's best and most expensive fillet brazed concoction, he clutched at his heart, said he would never speak to us again, and drove off in his BMW; maybe he was a man of principle after all!
When I moved on to Gazelle and Benelux Trek and Utopia and discovered Thorn bikes, I gave the purple Peugeot to the LBS for goodwill, and he sold it on, and I still see it, still with the last mirror I didn't trash on it, so they last forever in the hands of people who don't enter footbridge abutments with an inch to spare at either side at 45kph.
Of course nobody here would want such a great big clunking possibly two-pound mirror -- okay, maybe an exaggeration, but at least a pound and three-quarters, half the weight of the 30cm Abus Granit-X U-lock. But that's why some mirrors are cranked, to fit on the inboard space of straight bars and North Road bars, and touring and commuter bars, when the plug-end isn't available, nor any semi-outboard space as on drops, illustrated above by Il Padrone.
