SE (or presales as many places call it) is a great job as you can move into almost any direction you want very easily. You are essentially the ultimate all rounder - you must have extensive product knowledge, great communications skills, good sales awareness, marketing skills, work with the development team and services too - so you can then go into any of these directions actually very easily. I worked in presales for about 6 years and personally moved into product management which I love. If I wanted to I could move into development but I don't had those skills - but if I found a developer with a presales background I would snap them up immediately - would be a killer skill set combo; or a perfect startup founder.
So yes, I completely agree that SE or presales is the perfect job to do to get exposure to nearly all functional areas of business. And that is ideal for 'founder training' or simply if you don't know where you want to end up so want to learn what each part of the business is like.