The illustrator tools are terrible. But removing and replacing backgrounds in Photoshop has been spectacular with one caveat - they are less great if you give it any instruction. If you use the generative fills with prompts the results are not at all great. However, if you leave the prompt blank it does a bang-up job matching the existing background set / scene.

Equally impressive has been generating parts of photos that are missing when extending the canvas size.

It tends to work best with photos that are “inside” (interiors) with strong geometric cues - but it has expertly matched lighting, backgrounds and their level of focus (or lack thereof).