Are electric coolers a good replacement for ice on hot days?

No, they’re not a magic replacement. Thermoelectric coolers plug into your car and only cool about 40°F below ambient, so on an 85°F day they struggle to hit 45°F—bad for raw chicken. Compressor coolers are the real deal (like mini fridges) but cost $500+ and are heavy. For most people, a decent cooler with ice is simpler and cheaper.