The light fixtures have been known to leak as the sealants / gaskets age. The weep holes acts as drains and will hopefully keep your lights from filling with water.
I've seen pictures of tail light fixtures that could double as fish bowls...especially when the lenses were installed upside down!
2022 R-Pod RP-192
2021 F-150 4X2 SuperCrew Lariat 502A, 3.5L Powerboost Hybrid, 3.55 gears, 7.2KW Pro Power, 1,840# Cargo, 7,000# Tow
It is better to have too much truck than to have too much trailer.