Layered causation is the Houston claim problem
A typical Harris County hurricane claim involves three separate coverages and at least two carriers. The wind lifts shingles and opens the envelope. Rain enters through that opening and destroys ceilings and insulation. Then the street floods and pushes water in at floor level. Under your policies, the first two are windstorm and the third is flood.
Anti-concurrent causation language lets an insurer deny an entire loss where a covered and an excluded peril combined. That turns the claim into an argument about sequence, and sequence is provable — high-water marks against the height of interior damage, the direction of material failure, the pattern of saturation through wall assemblies. Documented at the right time, it supports claims under both policies.

