I've always been weary of AC mains to directly heat the bed. It faster and will warp the bed, although that's not as big an issue with bed mesh leveling. But the imagine immediately reminded me of iPhone chargers that always have to hard transition from thick to thin where the cable always frays. They definitely should have used individual thicker wire in silicone, but hindsight is always 20/20
I previously "downgraded" from a 2.5mm thick 290x280mm 320watt heated bed to a 3mm thick 310x310mm 240 watt bed (both glass). Takes about 20% longer to heat but I run the bed at 110c for amazing ABS adhesion (about 11 minutes to heat). The original Glass bed started warping after a few weeks and the new bed has yet to show any signs of warp while also having more even heat spread out.
Side note; my printer uses thick gauge wire that syphons heat from the bed, would be nice if the wires ran to the middle of the bed. Although spread out, as to not effect the thermistor as much