Consequences of gutter water collecting in corrugated drain pipe

This is a follow-up question to Sloping ditch for corrugated pipe

The water coming down the gutter drain has a nominal velocity and will collect and transfer to an 80 ft run of corrugated pipe (to be installed). Assuming that the pipe is perfectly level until the very end where it slopes downward into the 25 ft section (see photo in link).

1. Will a siphon effect ‘pull’ the water along the 80 ft run into the 25 ft section?
2. What is the penalty / consequence if water is not completely eliminated from the pipe and sits in the pipe until the next rainfall?

Assume a Florida venue: freezing is not a concern.

I realize that a nominal slope is the key to forcing the water naturally from the drain to its target destination, however, the question is posed to understanding the worst-case dynamics. Unfortunately, I think there is only 10 of depth available for the 80 foot run. As much as I like the idea of a column of water pressure pushing the water through the 80 foot run, I think that would require a watertight seal, which is not long-term reliable.