Curvature of Earth's surface notwithstanding, if I get into a pickle in the backcountry the only thing I'm likely to be signaling is an aircraft, in which case the planet's curvature will be largely irrelevant. In this I'm encouraged that the "standard" 18650 light tested in the video was visible at eighteen miles, which means that there is a pretty decent chance of a pilot detecting an emergency signal aimed at an aircraft "only" ten miles away. Of course, a Rescue Laser can easily reach 20 or 30 miles, depending on which model is being carried, but a single-purpose laser signaling tool is probably overkill for all but the most remote adventures (or misadventures, as the case may be).
As a practical matter the monster throwers shown in the video come with a significant space and weight penalty: they are prohibitively bulky and heavy for hunting or backpacking, although I can see some utility if they are carried in a vehicle, a canoe, on horseback, or perhaps in an ATV. The space and weight considerations involved in day hikes, hunts, or backpacking argue for carrying a 6P-sized light or smaller, with some variation depending on the length of the adventure and the kind of terrain being traversed. (For example, I can justify carrying a 21700-fueled light in a desert environment or an excursion in the Sierra Nevada range, where the terrain is more open, and greater power and more throw are useful.) But since rescue lasers are smaller, lighter weight, and less costly than any of the monster throwers currently available, if serious emergency signaling is something you need to plan for, I'd go with a dedicated laser (not an LEP, but a real signaling laser). As an added bonus, the lasers are visible in daylight, not just at night.