Low Flat is Flat with a shortened tip — roughly a millimetre less height, which sounds trivial and isn’t. Sitting lower changes the bey’s attack angle and how hard it drives into the rail, and the result is noticeably more speed and more aggression than standard Flat delivers. It also shortens the window in which any of that is useful.
Competitive opinion on Low Flat is genuinely split, and it tends to land a tier below the safer attack options. The problems are self-inflicted: stamina is even worse than Flat’s, and the self-knockout rate is high enough that it’s usually described as a bit for experienced launchers rather than a general recommendation. If the first few seconds don’t produce a burst or a ring-out, Low Flat has nothing left to fall back on.
It belongs on blades with violent contact shapes and plenty of recoil. Wear is a real cost here — the constant rail contact chews through the tip and gears faster than most parts in the system, and players who main it typically keep spares. Those who find it too swingy revert to Flat.