What's the difference between a PAR38 bulb and a dedicated floodlight fixture?

PAR38 bulbs (like the Sunco and GE picks) screw into existing E26 sockets, so they're the easy retrofit for homes that already have flood housings. Dedicated fixtures like the LUTEC and Philips integrate the LED array, driver, and PIR sensor into one sealed unit, which specialist subreddit threads note tends to last longer outdoors because there's no socket joint to let moisture in.