Do you think KEE's background is important? According to Mimin, it's a waste of time! Why indeed? Let's just give a case example...
Source : https://belfot.com/
In the photo above, with a blue background, the main focus is directly focused on the white bird and there is even a greenish contrast around the eyes. It's even cooler... The background and object colors look harmonious.
Source : https://belfot.com/
Meanwhile, in the second photo above, the object is the same but the results are very different... the background looks busy with leaves and twigs which, although blurry, are still disturbing.
That's why it's not wrong to say that the background is important because usually the area can be up to 60% of the photo area. Make sure your background supports the object of your photo and doesn't look chaotic.