It's absolutely fine. This is how it looks at the mo:

https://blog.making-spaces.net/2017/01/20/the-open-plan-work-space-final-reveal/

And yes, it's just plaster, so can be painted over which doesn't affect the magnetic function at all. Here's a photos from another project with a magnetic wall which had a mural painted over the top in a playroom.

Magnetic Playroom · More Info

Thank you. Beautiful work.

Brilliant project. Does any of the plaster chip off if the stronger magnets are removed to reposition?

Zed Zed - Not at all. I've had mine for about 4 years now and it's still great, even though it's been left unsealed. And I have some VERY strong magnets on there.

Thanks so much for the information. I feel I've seen the future with your project. LOL. I am very serious now about using the same/similar product in my build!