Gwiv, you get around town !! They just unveiled their sign and windows several days ago.
I am surprised that it took so long for one of the boba tea shops to open a franchise here in Chicago. Chicago's small population of Chinese and Asians was probably a deterrent.
I personally don't really like the boba teas from any of the powdered boba tea franchises that I have been to, such as, Quickly, 168, St. Alps. They just taste so artificial. The snacks are usually just okay - fishballs and snacks from the frozen food aisle fried or drenched in some sauce. These restaurants tend to appeal to a younger, hipper Asian crowd - young HKers, Taiwanese, and others with a generous stipend from mom and pop who are running a business back in Asia. The style is very Japanese, the colors are vibrant, and the staff is young.
St. Alps will probably give Joy Yee a run for their money. But IMHO I think that Joy Yee has already gotten a great foothold on the Chicagoland market and St. Alps will be the one challenged. (I also am not a fan of Joy Yee's food. However, I do appreciate their fruit slushes every so often.)
In regards to a hidden tea house in a back room somewhere, eh . . . . I don't think so. Not enough wealthy, privileged, and educated Chinese patriarchs and matriarchs to support such a "frivolity." At least, not yet - seen a couple of Ferraris scooting about the neighborhood driven by young Chinese. Give it a few more years. Most of the patriarchs/matriarchs are still very hands-on in their self-built businesses and too busy to enjoy the luxury and expense of expensive teas.