As somebody who started in software at a non-tech company, my first reaction to this was horror. On second thought, it seems like fine advice as long as your first job at the advertising firm is as a brand manager, or at a manufacturing firm you're in logistics, etc. I.e., if you are primarily an entrepreneur who might someday want to start a tech company, then by all means get some first-hand practical experience with fundamental problems of interest to your someday-customers.

My advice is to make sure wherever you are, you're working on the thing that senior management care most about. That's where you'll have the opportunity to work towards ambitious goals with the best mentors and exposure to real-world consequences.