Quite some time ago, someone invented a device that spritzed the scent and taste of chocolate into your mouth. The idea was to give you the experience of eating chocolate without the calories. The fact that shelves are not stocked with such devices is an indication that taste is not the only reason we eat things that we enjoy. There are far more factors that go into the enjoyment of food than how it hits your tastebuds.
Products like this marron (chestnut) and chocolate gum are attempts to allow people to enjoy the sweets they like without the calories they don't want. Unfortunately, such things never end well. I've tried chocolate gum before and it is distinctly unsatisfying. I'm not sure if the chestnut gum, an experienced divorced from the creamy, carby textural delights of marron consumption, would fare better, but I'm pretty sure I'll try it if I come across some.
Incidentally, the chocolate gum is available on eBay for $3 a pack, but the marron is not. Somehow, this is not surprising as I'm guessing most foreign folks aren't going to like chestnut gum any better than something like, oh, peanut butter gum.