It is probably an industry given that this type of quick fitting of a replacement radiator is acceptable, but not to my eyes or the fact that 2 x 90-degree elbows so close together will cause flow disturbance. If the fitter was rushed and/or could not be bothered to lift the floor, then at the very least he could have cut lower and then pulled an offset on his bender and used one st coupling, which would have made a far neater and more system friendly job.
He/she would not have gotten away with it if I were paying

A lack of pride in work produced seems to have gone by the wayside these days
EDITED for a PS .. pumped heating systems are too forgiving and also allow fitters to get away with shoddy work. Before fully pumped systems when gravity heating relied on thermosyphon, great thought had to be exercised by pipe fitters.