Actually, a degree in marketing is very, very helpful in advertising, no matter what your area of expertise.
Now, if you’re asking “how hard is it to get a job as copywriter with a degree in marketing,” that’s a different question all together. The qualifications for being a “creative” in advertising is different than those of an Account Executive or Media Buyer.
Basically, if you’d like to work in the creative side, you’ll be needing a portfolio/book, which is a collection of spec ads that showcase your talents. (Spec=speculative, i.e. fake.)
So, to sum up, without knowing what area you want to work in–creative or accounts–the answer could be either “yes” or “no.”
Add details and I’ll do the same.
:)