Specialty Hot Dogs.
There's really not much else to say here - obviously what they make is delicious, because it is hot dogs. And it fills a niche market that undoubtedly exists. It is also pricey for something that you can make for a couple bucks at home in less time than it takes to make kraft dinner.
All you have to do is math: you would otherwise buy Toronto streetmeat for 3 bucks (3.50 for a vegetarian, 4 for a sausage). At Frank's you can top that with Breaded Shrimp, Kimchi Noodles, Eggs and Bacon, et al. Sometimes, this will be a great idea. Is it at whatever point in time you happen to be at College in the Kensington district?
Last night my dog partner and I split a Po Boy vegetarian dog. It was a great idea. We did the math.