1. For many maintaining currency is a baseline requirement for licensing or registration, and is often a pre-requisite hurdle to be considered for certain roles. But more importantly, professional development requirements are in place to ensure consumers are delivered capabilities consistent with what should be expected by the consumer and society generally.
2. It doesn't matter what field you work in. The world changes and that means we need to change the way we work, too. The Oxford Dictionary defines a professional as someone who is "competent, skilful, or assured." If your knowledge or skills are outdated, you're not competent. Ongoing professional development is the only way to ensure that you are competent and skilful in your role.
Source: https://www.opencolleges.edu.au/careers/professional-development