Though many people don't consider 20700-like form factor promising for a flashlight in the near future, I do like this battery to be used in some scenarios.
Let's take the NITECORE TM03 as an good example. Its design is to drive an XHP-70 LED with single 18650, delivering a TURBO mode output of 2800 lumen (actually it's 3000+ lumen according to some reviews). Of course in this mode a lot of current must be offered by the single battery (8~10A, even larger when the battery voltage drops), and so you should use a cell that is capable of delivering ~15A for safety (so NITECORE has a dedicated high drain cell for this light). Then the candidates with largest capacity are Sony VTC6, Samsung 30Q, and LG HG2. These cells have a capacity of 2900~3100mAh (same as the dedicated NITECORE cell).
However sine the NCR20700B is capable of 15A discharging (you can see its curves
here), we can surely use this new cell to replace the 18650s mentioned above and gain ~30% or more runtime. And the change in the light form factor is almost negligible. This upgrade is definitely appealing to me!
Similar upgrade can also be made for other flashlights that require a current of 10A+.
And since the curves of NCR20700B is good (many 5000~5200mAh 26650 cells perform poorly under a load of ~10A or above), manufacturers like ACEBEAM/OLIGHT who make 26650 flashlights today can make a "tiny" version of them and offer a longer TURBO runtime. The reason is, as you may know, the ACEBEAM EC50 GEN II and EC60 can no longer output TURBO when the battery voltage drops to 3.7V~3.8V. This is because the ACEBEAM 26650 cell itself cannot stably deliver 10A+ (many others cannot either). Now that since the 20700 can do 15A, ACEBEAM can build a tiny version of EC50 GEN II / EC60 for this cell and remove the voltage restriction on TURBO mode.