Q: What is the benefit of having a cascading restraint clause?

A: By way of background, restraint clauses are generally considered unenforceable unless they can be shown to be reasonably necessary to protect the business interests of the employer. If a court finds a restraint of trade clause to be unreasonable, it will most likely result in the whole clause being unenforceable.
With cascading restraint clauses, each variable (e.g. 2 years, 1 year, 6 months) is treated as an individual clause, and is severable and independently binding. This means that where one level of restraint is deemed too harsh or unreasonable, the employer can look to enforce a lower level of restraint without the entire clause being invalidated.

Please note: The answer is correct at the time of publishing. Be aware that laws may change over time. Refer to Restraints of trade for current advice.