I bet that PLA-HF will come when Bambu Lab creates a printer that hits north of 700 mm/s print speeds with 30,000 mm/s2 accelerations - because then it’ll be a necessity. As it is now, with the current crop of printers offered, we don’t really need a high flow PLA, since Bambu Lab filaments clocks in at around 35-40 mm3/s, and that’s only a limiting factor for rare situations - such as using a 0.8mm nozzle at high speeds when using 3rd part hotend/nozzle, such as the one from E3D. With the stock hotend and nozzle, we’re closer to 18 mm3/s although Bambu Lab’s own PLA profiles states 21 mm3/s (I have made custom presets that dial them down to 18 mm3/s because our printers simply can’t maintain the correct wall thickness if run at 21 mm3/s).