The way I see it, a tidally locked planet is an easier find, because of the high variance in surface temperatures. Relatively rotating planets will have far narrow variances, making most of them uninhabitable based on temperature.
Instead of needing to find a rotating planet exactly in the "Goldilocks zone", any planet whose surface is hot on one side but cool on the other, such that the range of temperatures in some part of it lies in the zone, is acceptable, because you can suppose a zone of habitability on the edge of light and shadow.
I'm guessing that's easier because if the planet is a bit too hot on average, you can shift the zone into the shadow; and if it's too cool on average, you can shift the zone into the light. If the planet rotates, you've got a bigger problem, especially if it's too hot, because you need to find / build shade.