I have long felt that for most real estate photographers, it's not a necessary tool, despite the indisputable fact that they are very useful in many circumstances. But that assumes you are a full-time real estate photographer, possibly shooting a mid-to-high volume of homes where efficiency is just as important as quality. In that scenario, logically, I feel that a zoom lens is far more versatile and efficient.
I have also observed in various online groups where photographers share their photos that when a tilt-shift lens is used, it is rarely used beyond the most basic problem-solving use cases (higher camera height in a kitchen, and shifted down; or shifted up for an exterior photo), which can be done 99% of the time by using the "fake tilt-shift method", where you intentionally tilt the camera to get the framing you want, and correct verticals in post with a slight crop.
In that case, I don't see any value in using a tilt-shift lens for real estate photography. It is not adding anything to the image compared to faking it. The loss in pixels and the marginal loss of image quality is hardly worth discussing when the photos are destined for the MLS, and there are a couple of associated downsides: First is, if you are spending time changing lenses instead of using a far more versatile zoom lens (loss of time, less efficiency; time = money), and the second is, if you are not changing lenses and are instead shooting all of your photos at one focal length (no variety, default mode of operation instead of using a focal length that better suits the scene in front of your camera). Compositions can change dramatically at different focal lengths and a zoom lens can offer many more possibilities when moving quickly.
I own tilt-shift lenses, and they are AMAZING creative tools and problem-solving tools. There simply is no replacement for what they can do. As soon as a photographer embraces all of the lens's movements and begins seeing new compositions that were previously impossible, there is no going back to conventional lenses.
There is a limit to what can be accomplished with the "fake tilt-shift method". You can only get away with it to a point, beyond which, objects in the photo become too distorted. This is where a tilt-shift lens surpasses the work-around method with a conventional lens. It is far more versatile while still retaining the correct perspective with minimal or no distortion.