There was a time when all racks were 3 point fixing and steel. My first racks in the 80s were and I camped and toured on them... So yes they are ok
^ I've had exactly that Bontrager rack on my bike for about two years, I'm surprised at how stiff it is seeing as one arm is held on with a P-clip to clear the brake (frame was designed for centrepulls but I'm using sidepulls, so the rack eyelet on that side isn't usable). Carried about 20kg on it for a day before and it was fine even with one P-clip, no word on long-term durability though, as most days I only use it to carry my lock!
Old CTC member comment coming up.....
There was a time when all racks were 3 point fixing and steel. My first racks in the 80s were and I camped and toured on them... So yes they are ok