Pop-up shops will help the overall economy by producing more revenue and therefore producing more business and money for people to use throughout the industries. Their relevance to the overall economy is certain to only make it better. They can provide more business transactions to take place in more locations when needed.
Pop-up shops create a strong interactive marketing avenue. Even though pop-up retail only exists for a carefully orchestrated amount of time, both brands and the real estate end benefit from Pop-up shops. The flip side, the time constraint serves to bring about a rush of excitement as well as a sense of urgency in the buyer for the brand.
I agree -- with qualifications. Pop-ups can be great for bringing new products and services in to test for market viability, especially in more rural areas that aren't in test markets already. Is it true that most pop-ups hire locals? If so, what happens when those jobs leave? Are these employees invited to move with the shop? Are they ever able to buy one? It's one thing for to open and run a pop-up yourself and another to stay put long enough for someone to depend on the income and then leave.
Pop-up shops are healthy for the economy because they stimulate it without having low points. If you look at Halloween pop up stores, they're available for a specific time period. You can purchase the items you need but once the store would become irrelevant, like after Haloween, it closes to avoid unnecessary rent charges. People will purchase their costumes or decorations, thus circulating money, and the shop closes shortly after.