It can be answered by reversing the question. Would it be ethical for your current employer to ask you to do a job outside of the scope he explicitly hired you

It can be answered by reversing the question. Would it be ethical for your current employer to ask you to do a job outside of the scope he explicitly hired you for ? I.e. would you do photoshop work in a pinch, even if you're paid as a database engineer ? Would you help brainstorming the UX of a product while you were brought in to deal with performance bottlenecks ? If you think you should put your whole knowledge and skillset to solve any problem coming your way, no matter what's written on your contract or business card, you should allow yourself to expand this knowledge and skillset during work hours as long as there is no direct damaging effects to the things you work on.