Using Associativity to Reduce Number of OR Gates
The first expression has one, 3-input OR gate. The second has two, 2-input OR gates. These two expressions are logically equivalent.

Whether either one is simpler than the other depends on your definition of simple. Does simple mean fewer gates or does simple mean that you only use 2-input gates? In the real world, optimization is usually done to minimize silicon area and propagation delays.