Tha reservoir capacitor voltage may only be 280V when the LEDs are lit, but when you turn them off it will rise to peak rectified mains, i.e. 375V.

Fuses may be medieval, but they reliably protect systems from over current faults. They are well understood, which is why they are mandatory in critical systems. They do however have large tolerances and operate slowly, making them completely useless for protecting LEDs.