Well yes of course, however it depends on what sort of job you are applying for.
Overall, it demonstrates that you have another skill set, have successfully attended a course and received the official accreditation, and more than likely if the company doesn't use Affinity software, that you'll be able to pick up whatever they do use, quickly.
Not everyone who uses Affinity or Adobe are professionals in the field of, say, graphic design, however knowing how to use the programs might just give you an edge over someone else as there maybe an element of it in the role.
At the end of the day, it's hardly a big issue is it? Merely something the company could arrange so that new learners have a course to use to learn how to use the program, and receive a certificate at the end of it. Just a small, positive thing.