Don’t really see a major disagreement here other than the direction of primary exposure, belts some how being protected behind a fan when the main exposure is from the sides, etc. Puddles have a lot more corrosion potential than rain/snow. Point isn’t to seal, that’s unrealistic, but rather to deflect enough that every puddle isn’t pressure washing your engine bay with salt water. An example car where this was a major issue was a 97 galant, which had the crank shaft low and in alignment with the water jet from the driver side tire. There was a splash shield that directly intercepted the inner spray. I would classify that case as more than nominal protection.