No, a TTL flash is not an exaggeration for real estate lighting, and Scott Hargis developed his real estate business primarily with manual Nikon flashes and activated them with his "silly" ("S") optical slave mode, which It does not even use proprietary wireless system compatible with CLS TTL. He also often did not use brackets or modifiers, but simply placed the flash on top of a door to bounce the flash in the corner of a room to get diffuse light. His real estate photography course at lynda.com has videos that show how he does it.
The YN-600EX-RT II is designed to work in Canon's "RT" radio-frequency activation system, so it can do TTL, HSS, etc. Through the radio. But, even if you need the ability of TTL to quickly adjust the power of the flash based on the measurement in a real estate situation, it is a matter of how you prefer to work.
And what you may not be considering is a future expansion. While spotlights are sufficient to illuminate smaller rooms, lighting the exterior of a home in a very large / tall area may require something more powerful than a spotlight. And at this time, the Yongnuo RT gear does not include anything bigger than the flashes. Phottix and Jinbei make studio strobes that work in the RT system. And Godox's own radio system includes lights that extend from small spotlights to studio strobes, with flashes of bare bulb.
There is also the problem of what can happen if you choose to swap camera brands in the future. Many of Canon's handles are currently leaping into view for Sony's frameless full-frame cameras or the Fuji medium format. The RT system only works for Canon. If you change the camera systems, you will buy your lights again. Jinbei, Godox, Phottix and Profoto are creating cross-branding systems in which the only piece of equipment that needs to match the brand of the camera is the transmitter unit in the camera. At this time, Yongnuo only manufactures TTL equipment for Canon and Nikon, and that equipment does not work with cross marks (that is, the equipment for Canon is incompatible with the Nikon equipment).