Mini-catio gives indoor cats a breath of fresh air
Here is a mini-catio and I like it. It is a compromise between a proper catio - a cat enclosure attached to the side of a house one side of which is open to the elements behind a protective mesh to stop the cats getting out - and access to the outside which can often be unsafe.
And this little mini-catio, as I have described it, is cheap to purchase and quick to put up. That will appeal to many people. I would expect that it could be erected in as little as an hour. The only difficulty will be providing a cutout panel for the window through which the cats have access to the tiny enclosure. But these sorts of tiny enclosures can be attractive to domestic cats who are confined to the indoors.
We know how cats like to rest in their favourite place (which they tend to change on a daily basis) and therefore a little enclosure like this can add to their menu. It would be an extra place where they can go to. It would add a little bit to their lives and make it more colourful and interesting. In short, it would be a way of enriching their environment inexpensively. For that reason, I would heartily recommend it.
Anything that can make the life of a full-time indoor cat were enjoyable must be welcome. It won't suit everybody because a lot of people are too houseproud to have this sort of construction sticking out of it. It doesn't look great but it is effective.
On a separate subject, I note that the person is jacking up the tunnel with Tidy Cats litter boxes or that is what it appears. The lightweight version of this cat litter is problematic as allegedly there have been some deaths from it because it creates too much dust. You might like to read about that by clicking on this link.