Bluetooth's current location technology isn't particularly exacting. Its proximity features can tell you when you're close, but not which way to go -- and the position features are only accurate down to the meter level (about 3.3 feet), which can only help so much when a gadget falls between the couch seats. It's about to improve by leaps and bounds, however, The Bluetooth SIG has introduced direction finding support in its 5.1 standard to make location tech far more precise and overall useful.
If you're using a compatible device, proximity sensing can show you the direction of a signal to give you an idea of where to look. Positioning, meanwhile, can take advantage of direction finding to pinpoint objects down to the "centimeter-level" (0.4in). You'd not only know that your keys fell into the couch, you'd know which cushion to check.
It'll take a while before this technology reaches the real world. The Bluetooth 5.1 spec is only available to developers as of today, and it's going to take some time before device makers and software implement its improvements. Whenever that happens, though, it could spur a wave of gadgets that don't require (or supplement) GPS or WiFi to offer highly accurate location data. It might also be helpful for stores, airports and other places that rely on Bluetooth beacons to help you navigate.