On the problem of Spatial Path

[yiyi-today]

In 3.1 Spatial Path, there is a sentence "Based on this observation, we propose a Spatial Path to preserve the spatial size of the original input image and encode affluent spatial information. ". But in 3.1 Spatial Path, this path extracts the output feature maps that is 1/8 of the original image. What does it mean to preserve the spatial size of the original input image? Why does the paper say to preserve the spatial size of the original input image?
I'm looking forward to your reply. I'm very confused about this question. Thank you very much！