My first job was at a large casino as a systems analyst. The casino switched CMS software and went to an AS400 RPG based application named ACSC. I took it upon myself to learn the database of the application and also to learn RPG programming (shudder).

This lead to my first software development position at a large international bank.

I worked as an RPG developer for three years then I pivoted to SQL Server/C#.

So yes knowing a not so famous language benefited me.