1. has the best stress, and the bearing capacity of arched roof is higher than that of flat roof.

2. reduce the snow load, and the top of the arched greenhouse is not easy to accumulate snow;

3. Prevent dew from dripping. The arched roof is exposed inside, and dew will flow down the roof instead of dripping directly (peach-shaped greenhouse is the most obvious).

4. Improve the lighting effect, and the arch is easier to obtain uniform illumination than the flat roof or inclined roof;

..... there are other possibilities. Think so much for the time being.