If you know the final output size—work at that size.
If there's a possibility you will be using the image at different sizes then yes, work at a larger size, it will give you more flexibility, as Alex Fregon says. But if the image is going to be used at one specific size, work at that size.
If you work at a larger scale then shrink the image after exporting, you're resampling the text and logo and anything else you've added to the image—unnecessarily. You're likely to get artefacts or unwanted [anti-]aliasing.
This Image was created at the correct size:
This Image was created at a larger size then reduced in size later:
Notice the halo around the text and anti-aliasing. If we compare the images it is a lot more noticeable:
Another reason to work at your final size is avoiding unrealistic expectations. You're working at 3x your final output size, you finish your edits, export at a different size and wonder why your image doesn't look as good as it did. You then spend just as long trying to get you final image looking as sharp as it did 3 times bigger. You're just adding an unnecessary step.