"Hammerhead" sounds like an American term to me. "Tadpole" seems universally recognised, at least in the Recumbent world.
Trikes, to me, before I became infected with Recumbentitis, suggested an eccentric British phenomenon where someone took a perfectly good road bike and attached an extra wheel, introducing a hitherto unknown world of upsidedown -ness and new knowledge of roadside ditches to people who had previously thought they were competent two wheeler riders. A complete new skill set required, perhaps earned through a tough apprenticeship. Most seen as an extra wheel on the back, though some vintage ones have the extra one on the front. I don't know whether the twin front wheel version would be any easier to learn to ride. Perhaps someone out there with experience of both can enlighten. us.
Having become a recumbent rider I'm not about to venture on to anything new in the upright world, going back to the neck, shoulder, wrist and foot pains with the addition of new and exciting ways of falling off and breaking a leg.
Being a long term motorcycle rider I'd long fancied trying out a cycle car, a sort of velomobile for motorcyclists, but never managed it. 2 wheels at the front, one at the back, driven by a long chain from a suitably humungous V -twin engine at the front between the wheels. So when, as a rookie recumbentist, I came across various tadpole recumbent trikes on such places as
ebay the concept sort of chimed with me. Nevertheless, two wheelers are my choice for various reasons.
So to get back on thread, there's 1) The comfort 2) The view 3) The feeling of freedom that having two wheels brings.
Since even when I rode uprights I never rode the sort of sleek, speed orientated bike that screamed "wear Lycra or you'll look a pillock on this" wearing everyday clothes is just something I do, anyway.