Ilia,I take your point about needing definitions. I am thinking particularly of 'photo-realism'.
My original post was immediately after I attended an exhibition of contemporary painting and I found myself in front of a watercolour depicting a seaside scene. The painting was technically a masterpiece. I can only imagine the time and trouble taken by the artist to produce a work of such technical perfection.
Nevertheless, my immediate and longer lasting reaction was - why bother? If the artist had just taken a photo of the scene and had it enlarged, he would have saved himself a lot of trouble. Just recently, I have seen many similar examples.
On a more general and personal note, I find 'illusionistic' painting sterile. I should make clear, however, that I tend to regard Impressionist work as 'semi-abstract'.