if you are talking about the gelatin-based dessert that is not spreadable on toast (actually, that sounds tasty) we call it gelatin. There’s a brand name that has worked its way into our brains, though. We tend to call it Jell-o. Even if it’s an off brand.
We also do have something we call “jelly.” Jam has fruit pulp, while jelly is strained and just the gelatin/fruit juice/sugar mixture.
The car thing is simple. We’re idiots that fall for marketing ploys. If you forget your keys, or if you can’t access them, just punch in the code and you’re in! Most people I know don’t use it. It’s not standard on many models. It’s in the more premium car packages. It was popular around the mid-2000s. Keyless entry is starting to gain traction now. You can use your smartphone or a little device that comes with your keys to stand a couple of feet away and unlock your car without pressing buttons or using an actual key.