I bought a couple and returned them - because the ones I bought (unknown to me) were plug in not hard wired - is this normal?
I would say it's common. At least in big box stores.
They tend to carry what sells most to the general public and I would guess that most consumers don't know a knockout from a knockwurst and aren't going to be hard wiring many fixtures.
Costco had some really cool looking weather-tight fixtures but not only were they plug-in, you couldn't even plug them into a switched outlet. They were expecting you to only use the internal motion sensors to turn them on and off. There was no by-pass to use them with a switch.
Just what I need, to be working under my car and have the garage lights turn off because the sensor can't see me.
And, being Costco, they were less than half the price of similar hard-wired fixtures from an electrical supplier. So they were laughing at me every time I walked down the aisle.
But, as the fixtures laughed, the replacement tubes beckoned. The box said you could just plug them into an existing T8 fixture.
One of the fluorescent fixtures in my garage was flaking out. It looked like the ballast was providing run voltage but not starting voltage. the tubes were flickering dimly. I figured that since the LEDs don't need a starting voltage, they might just work with the wonky ballast.
And sure enough, they worked great, plug and play, no fuss no muss. And they're brighter than the fluorescents, too.